System and method for tracking and assessing movement skills in multidimensional space

ABSTRACT

Accurate simulation of sport to quantify and train performance constructs by employing sensing electronics for determining, in essentially real time, the player&#39;s three dimensional positional changes in three or more degrees of freedom (three dimensions); and computer controlled sport specific cuing that evokes or prompts sport specific responses from the player that are measured to provide meaningful indicia of performance. The sport specific cuing is characterized as a virtual opponent that is responsive to, and interactive with, the player in real time. The virtual opponent continually delivers and/or responds to stimuli to create realistic movement challenges for the player.

RELATED APPLICATION DATA

This application is a continuation of U.S. application Ser. No.11/414,990, filed May 1, 2006, currently pending and to be issued asU.S. Pat. No. 7,359,121; which is a continuation of U.S. applicationSer. No. 11/099,252, filed Apr. 5, 2005, issued as U.S. Pat. No.7,038,855; which is a continuation of U.S. application Ser. No.10/888,043, filed Jul. 9, 2004, issued as U.S. Pat. No. 6,876,496; whichis a continuation U.S. application Ser. No. 10/197,135, filed Jul. 17,2002, issued as U.S. Pat. No. 6,765,726; which is a continuation of U.S.application Ser. No. 09/654,848, filed Sep. 5, 2000, issued as U.S. Pat.No. 6,430,997; which is a continuation of International ApplicationPCT/US99/04727, filed Mar. 3, 1999, which was published under PCTArticle 21(2) in English, abandoned; which claims priority from U.S.Provisional Application No. 60/121,935, filed Feb. 26, 1999; and whichis also a continuation-in-part of U.S. application Ser. No. 09/173,274,filed Oct. 15, 1998, issued as U.S. Pat. No. 6,308,565; which is acontinuation-in-part of U.S. application Ser. No. 08/554,564, filed Nov.6, 1995, issued as U.S. Pat. No. 6,098,458; and which is also acontinuation-in-part of U.S. application Ser. No. 09/034,059, filed Mar.3, 1998, issued as U.S. Pat. No. 6,073,489; which is acontinuation-in-part of International Application PCT/US96/17580, filedNov. 5, 1996, which was published under PCT Article 21(2) in English,abandoned; and which is also a continuation-in-part of U.S. applicationSer. No. 08/554,564, filed Nov. 6, 1995, issued as U.S. Pat. No.6,098,458. All of the above-mentioned applications are hereinincorporated by reference in their entireties.

BACKGROUND

1. Field of the Invention

The present invention relates to a system for assessing movement andagility skills and, in particular, to a wireless position tracker forcontinuously tracking and determining player position during movement ina defined physical space through player interaction with tasks displayedin a computer generated, specially translated virtual space for thequantification of the player's movement and agility skills based on timeand distance traveled in the defined physical space.

2. The Related Art

Sports specific skills can be classified into two general conditions:

-   -   1) Skills involving control of the body independent from other        players; and    -   2) Skills including reactions to other players in the sports        activity.        The former includes posture and balance control, agility, power        and coordination. These skills are most obvious in sports such        as volleyball, baseball, gymnastics, and track and field that        demand high performance from an individual participant who is        free to move without opposition from a defensive player. The        latter encompasses interaction with another player-participant.        This includes various offense-defense situations, such as those        that occur in football, basketball, soccer, etc.

Valid testing and training of sport-specific skills requires that theplayer be challenged by unplanned cues which prompt player movement overdistances and directions representative of actual game play. Theplayer's optimum movement path should be selected based on visualassessment of his or her spatial relationship with opposing playersand/or game objective. A realistic simulation must include a sportsrelevant environment. Test methods prompting the player to move to fixedground locations are considered artificial. Nor are test methodsemploying static or singular movement cues such as a light or a soundconsistent with accurate simulations of actual competition in manysports.

To date, no accurate, real time model of the complex, constantlychanging, interactive relationship between offensive and defensiveopponents engaging in actual competition exists. Accurate and validquantification of sport-specific movement capabilities necessitates asimulation having fidelity with real world events.

At the most primary level, sports such as basketball, football andsoccer can be characterized by the moment to moment interaction betweencompetitors in their respective offensive and defensive roles. It is themission of the player assuming the defensive role to “contain”, “guard”,or neutralize the offensive opponent by establishing and maintaining areal-time synchronous relationship with the opponent. For example, inbasketball, the defensive player attempts to continually impede theoffensive player's attempts to drive to the basket by blocking with hisor her body the offensive player's chosen path, while in soccer theplayer controlling the ball must maneuver the ball around opposingplayers.

The offensive player's mission is to create a brief asynchronous event,perhaps of only a few hundred milliseconds in duration, so that thedefensive player's movement is no longer in “phase” with the offensiveplayer's. During this asynchronous event, the defensive player'smovement no longer mirrors, i.e., is no longer synchronous with, his orher offensive opponent. At that moment, the defensive player isliterally “out of position” and therefore is in a precarious position,thereby enhancing the offensive player's chances of scoring. Theoffensive player can create an asynchronous event in a number of ways.The offensive player can “fake out” or deceive his or her opponent bydelivering purposefully misleading information as to his or herimmediate intentions. Or the offensive player can “overwhelm” hisopponent by abruptly accelerating the pace of the action to levelsexceeding the defensive player's movement capabilities.

To remain in close proximity to an offensive opponent, the defensiveplayer must continually anticipate or “read” the offensive player'sintentions. An adept defensive player will anticipate the offensiveplayer's strategy or reduce the offensive player's options to those thatcan easily be contained. This must occur despite the offensive player'sattempts to disguise his or her actual intentions with purposelydeceptive and unpredictable behavior. In addition to being able to“read”, i.e., quickly perceive and interpret the intentions of theoffensive player, the defensive player must also possess adequatesport-specific movement skills to establish and maintain the desired(from the perspective of the defensive player) synchronous spatialrelationship.

These player-to-player interactions are characterized by a continualbarrage of useful and purposefully misleading visual cues offered by theoffensive player and constant reaction and maneuvering by the defensiveparticipant. Not only does the defensive player need to successfullyinterpret visual cues “offered” by the offensive player, but theoffensive player must also adeptly interpret visual cues as they relateto the defensive player's commitment, balance and strategy. Each playerdraws from a repertoire of movement skills which includes balance andpostural control, the ability to anticipate defensive responses, theability to generate powerful, rapid, coordinated movements, and reactiontimes that exceed that of the opponent. These sport-specific movementskills are often described as the functional or motor related componentsof physical fitness.

The interaction between competitors frequently appears almost chaotic,and certainly staccato, as a result of the “dueling” for advantage. Thecontinual abrupt, unplanned changes in direction necessitate that thedefensive player maintain control over his or her center of gravitythroughout all phases of movement to avoid over committing.Consequently, movements of only fractions of a single step are commonfor both the defensive and offensive players. Such abbreviated movementsinsure that peak or high average velocities are seldom, if ever,achieved. Accordingly, peak acceleration and power are more sensitivemeasures of performance in the aforementioned scenario. Peakacceleration of the center of mass can be achieved more rapidly thanpeak velocity, often in one step or less, while power can relate theacceleration over a time interval, making comparisons between playersmore meaningful.

At a secondary level, all sports situations include decision-makingskills and the ability to focus on the task at hand. The presentinvention simulation trains participants in these critical skills.Therefore, athletes learn to be “smarter” players due to increasedattentional skills, intuition, and critical, sports related reasoning.

Only through actual game play, or truly accurate simulation of gameplay, can the ability to correctly interpret and respond to sportspecific visual cues be honed. The same requirement applies to therefinement of the sport-specific components of physical fitness that isessential for adept defensive and offensive play. These sport-specificcomponents include reaction time, balance, stability, agility and firststep quickness.

Through task-specific practice, athletes learn to successfully respondto situational uncertainties. Such uncertainties can be as fundamentalas the timing of the starter's pistol, or as complex as detecting andinterpreting continually changing, “analog” stimuli presented by anopponent. To be task-specific, the type of cues delivered to the playermust simulate those experienced in the player's sport. Task-specificcuing can be characterized, for the purposes of this document, as eitherdynamic or static.

Dynamic cuing delivers continual, “analog” feedback to the player bybeing responsive to, and interactive with, the player. Dynamic cuing isrelevant to sports where the player must possess the ability to “read”and interpret “telegraphing” kinematic detail in his or her opponent'sactivities. Players must also respond to environmental cues such aspredicting the path of a ball or projectile for the purposes ofintercepting or avoiding it. In contrast, static cuing is typically asingle discreet event, and is sport relevant in sports such a track andfield or swimming events. Static cues require little cerebral processingand do not contribute to an accurate model of sports where there iscontinuous flow of stimuli necessitating sequential, real time responsesby the player. At this level, the relevant functional skill is reactiontime, which can be readily enhanced by the present invention'ssimulation.

In sports science and coaching, numerous tests of movement capabilitiesand reaction time are employed. However, these do not subject the playerto the type and frequency of sport-specific dynamic cues requisite tocreating an accurate analog of actual sports competition describedabove.

For example, measures of straight-ahead speed such as the 100-meter and40 yard dash only subject the player to one static cue, i.e., the soundof the gun at the starting line. Although the test does measure acombination of reaction time and speed, it is applicable to only onespecific situation (running on a track) and, as such, is more of ameasurement of capacity, not skill. In contrast, the player in manyother sports, whether in a defensive or offensive role, is continuallybombarded with cues that provide both useful and purposely misleadinginformation as to the opponent's immediate intentions. These dynamiccues necessitate constant, real time changes in the player's movementpath and velocity; such continual real-time adjustments preclude aplayer from reaching maximum high speeds as in a 100-meter dash.Responding successfully to dynamic cues places constant demand on aplayer's agility and the ability to assess or read the opposing playerintentions.

There is another factor in creating an accurate analog of sportscompetition. Frequently, a decisive or pivotal event such as thecreation of an asynchronous event does not occur from a preceding staticor stationary position by the players. For example, a decisive eventmost frequently occurs while the offensive player is already moving andcreates a phase shift by accelerating the pace or an abrupt change indirection. Consequently, it is believed that the most sensitiveindicators of athletic prowess occur during abrupt changes in vectordirection or pace of movement from “preexisting movement”. All knowntest methods are believed to be incapable of making meaningfulmeasurements during these periods.

Known in the art are various types of virtual reality or quasi virtualreality systems used for entertainment purposes or for measuringphysical exertion. Examples of such systems are U.S. Pat. No. 5,616,078,to Oh, entitled “Motion-Controlled Video Entertainment System”; U.S.Pat. No. 5,423,554, to Davis, entitled “Virtual Reality Game Method andApparatus”; U.S. Pat. No. 5,638,300, to Johnson, entitled “Golf SwingAnalysis System”; U.S. Pat. No. 5,524,637, to Erickson, entitled“Interactive System for Measuring Physiological Exertion”; U.S. Pat. No.5,469,740, to French et al., entitled “Interactive Video Testing andTraining System”; U.S. Pat. No. 4,751,642, to Silva et al., entitled“Interactive Sports Simulation System with Physiological Sensing andPsychological Conditioning”; U.S. Pat. No. 5,239,463, to Blair et al.,entitled “Method and Apparatus for Player Interaction with AnimatedCharacters and Objects”; and U.S. Pat. No. 5,229,756, to Kosugi et al.,entitled “Image Control Apparatus”. These prior art systems lack realismin their presentations and/or provide no measurement or inadequatemeasurement of physical activity.

SUMMARY OF THE INVENTION

The present invention provides a system for quantifying physical motionof a player or subject and providing feedback to facilitate training andathletic performance. A preferred system creates an accurate simulationof sport to quantify and train several novel performance constructs byemploying: sensing electronics (preferably optical sensing electronicsas discussed below) for determining, in essentially real time, theplayer's three dimensional positional changes in three or more degreesof freedom (three dimensions); and computer controlled sport specificcuing that evokes or prompts sport specific responses from the player.

In certain protocols of the present invention, the sport specific cuingcould be characterized as a “virtual opponent”, that is preferably—butnot necessarily—kinematically and anthropomorphically correct in formand action. Though the virtual opponent could assume many forms, thevirtual opponent is responsive to, and interactive with, the player inreal time without any perceived visual lag. The virtual opponentcontinually delivers and/or responds to stimuli to create realisticmovement challenges for the player. The movement challenges aretypically comprised of relatively short, discrete movement legs,sometimes amounting to only a few inches of displacement of the player'scenter of mass. Such movement legs are without fixed start and endpositions, necessitating continual tracking of the player's position formeaningful assessment.

The virtual opponent can assume the role of either an offensive ordefensive player. In the defensive role, the virtual opponent maintainsa synchronous relationship with the player relative to the player'smovement in the physical world. Controlled by the computer to match thecapabilities of each individual player, the virtual opponent “rewards”instances of improved player performance by allowing the player tooutmaneuver (“get by”) him. In the offensive role, the virtual opponentcreates asynchronous events to which the player must respond in timeframes set by the computer depending on the performance level of theplayer. In this case, the virtual opponent “punishes” lapses in theplayer's performance, i.e., the inability of the player to preciselyfollow a prescribed movement path both in terms of pace and precision,by outmaneuvering the player.

It is important to note that dynamic cues allow for moment to moment(instantaneous) prompting of the player's vector direction, transit rateand overall positional changes. In contrast to static cues, dynamic cuesenable precise modulation of movement challenges resulting from stimuliconstantly varying in real time.

Regardless of the virtual opponent's assumed role (offensive ordefensive), when the protocol employs the virtual opponent, the virtualopponent's movement cues are “dynamic” so as to elicit sports specificplayer responses. This includes continual abrupt explosive changes ofdirection and maximal accelerations and decelerations over varyingvector directions and distances.

Further summarizing broad aspects of the invention, a testing andtraining system comprises a continuous tracking system for determiningchanges in an overall physical location of the player, in a definedphysical space; and a computer operatively coupled to the trackingsystem, for updating in real time a player virtual location in a virtualspace corresponding to the physical location of the player in thephysical space, for updating a view of the virtual space, and forproviding at least one indicia of performance of the player moving inthe physical space, wherein the at least one indicia is or is derivedfrom a measure of a movement parameter of the player. According to aparticular embodiment of the invention, the at least one indicia ofperformance that is or is derived from a measure of a movement parameterof the player includes an indicia selected from the group consisting ofa measure of work performed by the player, a measure of the player'svelocity, a measure of the player's power, a measure of the player'sability to maximize spatial differences over time between the player anda virtual protagonist, a time in compliance, a measure of the player'sacceleration, a measure of the player's ability to rapidly changedirection of movement, a measure of dynamic reaction time, a measure ofelapsed time from presentation of a cue to the player's initial movementin response to the cue, a measure of direction of the initial movementrelative to a desired response direction, a measure of cutting ability,a measure of phase lag time, a measure of first step quickness, ameasure of jumping or bounding, a measure of cardio-respiratory status,and a measure of sports posture.

According to another aspect of the invention, a method for testing andtraining includes the steps of tracking an overall physical location ofa player within a defined physical space; updating in real time a playervirtual location corresponding to the physical location of the player;updating in real time a view of the virtual space; and providing atleast one indicia of performance of the player moving in the physicalspace, the at least one indicia being or being derived from a measure ofa movement parameter of the player.

According to yet another aspect of the invention, a game system for twoor more players includes a continuous three-dimensional tracking systemfor each of the players for determining changes in an overall physicallocation of the respective player in a respective defined physicalspace; and a computer operatively coupled to the tracking systems forupdating in real time player virtual locations in a virtual spacecorresponding to the physical locations of the players.

According to a further aspect of the invention, a testing and trainingsystem for assessing the ability of a player to complete a task,includes tracking means for determining the position of the playerwithin a defined physical space within which the player moves toundertake the task, based on at least two Cartesian coordinates; displaymeans operatively coupled to the tracking means for displaying in avirtual space a player icon representing the instantaneous position ofthe player therein in scaled translation to the position of the playerin the defined physical space; means operatively coupled to the displaymeans for depicting in the virtual space a protagonist; means fordefining an interactive task between the position of the player and theposition of the protagonist icon in the virtual space; and means forassessing the ability of the player in completing the task based onquantities of distance and time, wherein the task comprises a pluralityof segments requiring sufficient movement of the player in the definedphysical space to provide quantification of bilateral vector performanceof the player in completing the task.

According to a still further aspect of the invention, a testing andtraining system includes tracking means for tracking a user's positionwithin a physical space in three dimensions; display means operativelylinked to the tracking means for indicating the user's position withinthe physical space in essentially real time; means for defining aninteractive protocol for the user; means for measuring in essentiallyreal time vertical displacements of the user's center of gravity as theuser responds to interactive protocols; means for calculating the user'smovement velocities and/or accelerations during performance of theprotocols; and means for assessing the user's performance in executingthe physical activity.

According to another aspect of the invention, a testing and trainingsystem includes tracking means for tracking a user's movement inthree-degrees-of-freedom during his performance of protocols whichinclude unplanned movements over various vector distances; display meansoperatively linked to the tracking means for indicating the user'sposition within the physical space in essentially real time; means fordefining a physical activity for the user operatively connected to thedisplay means; and means calculating in essentially real-time the user'smovement accelerations and decelerations; means categorizing eachmovement leg to a particular vector; and means for displaying feedbackof bilateral performance.

According to yet another aspect of the invention, a testing and trainingsystem includes tracking means for tracking a user's position within aphysical space in three dimensions; means for displaying a view of avirtual space proportional in dimensions to the physical space; meansfor displaying, in essentially real time, a user icon in the virtualspace at a location which is a spatially correct representation of theuser's position within the physical space; means for defining a physicalactivity for the user operatively connected to the display means; andmeans for assessing the user's performance in executing the physicalactivity.

According to a further aspect of the invention, a testing and trainingsystem includes a tracking system for providing a set of threedimensional coordinates of a user within a physical space; a computeroperatively linked to the tracking system to receive the coordinatesfrom the tracking system and indicate the user's position within thephysical space on a display in essentially real time; and wherein thecomputer includes a program to define a physical activity for the userand measure the user's performance in executing the activity, tocalculate the user's movement velocities and/or accelerations duringperformance of the protocols, and to determine a user's dynamic posture.

According to a still further aspect of the invention, a testing andtraining system includes a tracking system for providing a set of threedimensional coordinates of a user within a physical space duringperformance of protocols including unplanned movements over variousvector distances; a computer operatively linked to the tracking systemto receive the coordinates from the tracking system and indicate theuser's position within the physical space on a display in essentiallyreal time, and to calculate in essentially real-time the user's movementaccelerations and decelerations in executing the activity; and means fordisplaying feedback of bilateral performance.

According to another aspect of the invention, a reactive power trainingsystem includes a reactive training device which provides cues to elicitresponsive movements of a subject moves in at least two dimensions, anda resistive training device. The reactive power training device and thestrength training device are used in a training sequence.

According to yet another aspect of the invention, a method of reactivepower training includes performing a training sequence which includesreactive training bouts on a reactive training device alternated withtraining on one or more resistive training devices.

To the accomplishment of the foregoing and related ends, the inventioncomprises the features hereinafter fully described and particularlypointed out in the claims. The following description and the annexeddrawings set forth in detail certain illustrative embodiments of theinvention. These embodiments are indicative, however, of but a few ofthe various ways in which the principles of the invention may beemployed. Other objects, advantages and novel features of the inventionwill become apparent from the following detailed description of theinvention when considered in conjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

In the annexed drawings:

FIG. 1 is a perspective view of a testing and training system inaccordance with the invention;

FIG. 2 is a perspective view showing a representative monitor display;

FIG. 3 is a perspective view of simulated movement skills protocol forthe system of FIG. 1;

FIG. 4 is a perspective view of a simulated agility skills protocol forthe system of FIG. 1;

FIG. 5 is a perspective view of a simulated task for the system;

FIGS. 6 and 7 are software flow charts of a representative task for thesystem;

FIGS. 8 and 9 are software flow charts for an embodiment of theinvention;

FIG. 10 is a schematic representation of a simulated task that thesystem executes to determine Compliance;

FIG. 11 is a schematic representation of a simulated task that thesystem executes to determine Opportunity;

FIG. 12 is a schematic representation of a simulated task that thesystem executes to determine Dynamic Reaction Time;

FIG. 13 is a schematic representation of a simulated task that thesystem executes to determine Dynamic Phase Lag;

FIG. 14 is a schematic representation of a simulated task that thesystem executes to determine First Step Quickness;

FIG. 15 is a schematic representation of a simulated task that thesystem executes to determine Dynamic Reactive Bounding;

FIG. 16 is a schematic representation of a simulated task that thesystem executes to determine Dynamic Sports Posture;

FIG. 17 is a schematic representation of a simulated task that thesystem executes to determine Dynamic Reactive Cutting;

FIG. 18 is a perspective view of an alternate embodiment of theinvention which uses a first person perspective view;

FIG. 19 is a perspective view of the invention being used formultiplayer play;

FIG. 20 is a perspective view of an alternate embodiment of theinvention that uses multiple physical spaces and displays;

FIG. 21 is a perspective view of an alternate embodiment of the presentinvention which uses scaling factors;

FIG. 22 is a perspective view of an alternate embodiment of the presentinvention which can record movement protocols;

FIG. 23 is a perspective view of an alternate embodiment of the presentinvention which tracks the position of a player's upper extremities;

FIG. 24 is a perspective view of an alternate embodiment of the presentinvention which includes resistance devices that oppose player motion;

FIG. 25 is a perspective view of a prior art slide board;

FIG. 26 is a perspective view of a prior art ski simulation device;

FIG. 27 is a perspective view of an alternate embodiment of the presentinvention which includes an exercise device used by the player;

FIG. 28 is a plan view of a reactive power training system of thepresent invention;

FIG. 29 is a schematic view of the network connections of the system ofFIG. 28; and

FIG. 30 is a representation of a screen display of a testing andtraining system of the present invention.

DETAILED DESCRIPTION OF THE INVENTION Tracking and Display Systems

Referring now in detail to the drawings, FIG. 1 shows an interactive,virtual reality testing and training system 10 for assessing movementand agility skills without a confining field. The system 10 comprises athree dimensionally defined physical space 12 in which the player moves,and a wireless position tracking system 13 which includes a pair oflaterally spaced wireless optical sensors 14, 16 coupled to a processor18. The processor 18 provides a data signal along a line 20 via a serialport to a personal computer 22. The computer 22, under control ofassociated software, processes the data signal and provides a videosignal to a large screen video monitor or video display 28. The computer22 is operatively connected to a printer 29, such as a Hewlett PackardDesk Jet 540 or other such suitable printer, for printing output datarelated to testing and training sessions. The computer 22 may be coupledto a data inputting device 24. Such a device may be a mouse, trackpad,keyboard, joystick, track ball, touch-sensitive video screen, or thelike. The computer 22 may be coupled to the data inputting device 24 bya wired or wireless connection.

Referring additionally to FIG. 2, the monitor 28 displays a computergenerated, defined virtual space 30 which is a scaled translation of thedefined physical space 12. The overall position of the player in thephysical space 12 is represented and correctly referenced in the virtualspace 30 by a player icon 32. The overall position of the player will beunderstood as the position of the player's body as a whole, which may bethe position of the player's center of mass, or may be the position ofsome part of the player's body.

The player icon 32 may represent a person or a portion thereof.Alternatively it may represent an animal or some other real or imaginarycreature or object. The player icon 32 may interact with a protagonisticon 34 representing a protagonist (also referred to as an avatar orvirtual opponent) in the performance of varying tasks or games to bedescribed below.

The protagonist icon may be a representation of a person. Alternativelythe protagonist icon may be a representation of another object or may bean abstract object such as a shape.

The system 10 assesses and quantifies agility and movement skills bycontinuously tracking the player in the defined physical space 12through continuous measurement of Cartesian coordinate positions. Byscaling translation to the virtual space 30, the player icon 32 isrepresented in a spatially correct position and can interact with theprotagonist icon 34 such that movement related to actual distance andtime required by a player 36 (also known as an athlete or a subject) totravel in the physical space 12 can be quantified. The player icon 32 isat a player virtual location in virtual space, and the protagonist icon34 is at a protagonist virtual location in virtual space.

The defined physical space 12 may be any available area, indoors oroutdoors of sufficient size to allow the player to undertake themovements for assessing and quantifying distance and time measurementsrelevant to the player's conditioning, sport and ability. A typicalphysical space 12 may be an indoor facility such as a basketball orhandball court where about a 20 foot by 20 foot area with about a 10foot ceiling clearance can be dedicated for the training and testing. Itwill be appreciated that the system 10 may be adaptable to physicalspaces of various sizes.

Inasmuch as the system is portable, the system may be transported tomultiple sites for specific purposes. For relevant testing of sportsskills on outdoor surfaces, such as football or baseball, where theplayer is most relevantly assessed under actual playing conditions,i.e., on a grass surface and in athletic gear, the system may betransported to the actual playing field for use.

The optical sensors 14, 16 and processor 18 may take the form ofcommercially available tracking systems. Preferably the system 10 usesan optical sensing system available as a modification of the DynaSightsystem from Origin Instruments of Grand Prairie Tex. Such a system usesa pair of optical sensors, i.e., trackers, mounted about 30 inches aparton a support mast centered laterally with respect to the definedphysical space 12 at a distance sufficiently outside the front boundary40 to allow the sensors 14, 16 to track movement in the desired physicalspace. The processor 18 communicates position information to anapplication program in a host computer through a serial port. The hostcomputer is provided with a driver program available from Origin whichinterfaces the DynaSight system with the application program.

The sensors 14, 16, operating in the near infrared frequency range,interact with a passive or active reflector or beacon 38 worn by theplayer 36. The reflector or beacon 38 (collectively herein referred toas a marker) is preferably located at or near the center of mass of theplayer 36, although it may be located elsewhere relative to the player.For example the reflector or beacon may be attached to a belt which isworn about the waist of the player. The sensors report positions of thereflector or beacon 38 in three dimensions relative to a fiducial markmidway between the sensors. The fiducial mark is the origin of thedefault coordinate system.

Another suitable tracking system is the MacReflex Motion MeasurementSystem from Qualisys.

As is evident, a skilled person will recognize that many other suitabletracking systems may be substituted for or used in addition to theoptical tracking systems described above. For example, knownelectromagnetic, acoustic and video/optical technologies may beemployed. Sound waves such as ultrasonic waves, or light waves in thevisible or infrared spectra, may be propagated through the air betweenthe player and the sensor(s) and utilized to track the player. Suchwaves may be transmitted by an external source and reflected off of apassive reflector worn by the player. It will be understood that suchwaves may reflect off of the player or his or her clothing, dispensingwith the need for the player to wear a passive sensor.

Alternatively, the player may wear an active emitter which emits soundor light waves. Such an emitter may be battery operated, and maycontinuously emit sound or light waves when turned on. Alternatively,the emitter may emit waves only in response to an external signal orstimulus.

Multiple reflecting or emitting elements may be incorporated in a singlereflector or emitter. Such multiple elements may be used to aid intracking the location of the player. In an exemplary embodiment, threespaced-apart infrared emitting elements are incorporated in an emitterworn around the player's waist. The emitting elements are activatedintermittently on a rotating basis at a known frequency. Information onthe relative timing of the signals received from the various emittingelements allows the player to be tracked.

Alternatively or in addition such multiple elements may be used to trackthe orientation of the player's body as well as his or her position. Forexample, twisting of the player's body may be detected independent ofthe movement of the player by relative motion of the elements.

It will be appreciated further that one or more cameras or other imagecapturing devices may be used to continuously view the physical space.Image analysis techniques may be used to determine the position of theplayer from these images. Such image analysis techniques may for exampleinclude edge tracking techniques for detecting the location of theplayer relative to the background, and tracking of an item worn by theplayer, such a distinctively colored badge.

Any of the above such systems should provide an accurate determinationof the players location in at least two coordinates and preferablythree.

As is evident from the foregoing, tracking means used in the inventioninclude all such tracking systems described above which are suitable foruse in the invention.

In a particular embodiment, the position-sensing hardware tracks theplayer 36 in the defined physical space 12 at a sample rate of 500 Hz,with an absolute position accuracy of one inch or better in alldimensions over a tracking volume of approximately 432 cubic feet (9 ft.W×8 ft D×6 ft. H).

In the described embodiment, the player icon 32 is displayed on themonitor 28 in the corresponding width, lateral x axis, height, y axisand depth, or fore-aft z axis and over time t, to create a fourdimensional space-time virtual world. For tasks involving verticalmovement, tracking height, y axis, is required. The system 10 determinesthe coordinates of the player 36 in the defined physical space 12 inessentially real time and updates current position without any perceivedlag between actual change and displayed change in location in thevirtual space 30, preferably at an update rate in excess of about 20 Hz.A video update rate approximately 30 Hz, with measurement latency lessthan 30 milliseconds, has been found to serve as an acceptable,real-time, feedback tool for human movement. However, it is morepreferable for the update rate be even higher, in excess of about 50 Hz,or even more preferably in excess of 70 Hz.

The monitor 28 should be sufficiently large to enable the player to viewclearly the virtual space 30. The virtual space 30 is a spatiallycorrect representation of the physical space as generated by thecomputer 22. For a 20 foot by 20 foot working field, a 27-inch diagonalscreen or larger allows the player to perceptively relate to thecorrelation between the physical and virtual spaces. An acceptablemonitor is a Mitsubishi 27″ Multiscan Monitor. It will be appreciatedthat other display devices, such as projection displays, liquid crystaldisplays, or virtual reality goggles or headsets, may also be employedto display a view of the virtual reality space.

The computer 22 receives the signal for coordinates of the player'slocation in the physical space 12 from the processor 18 and transmits asignal to the monitor 28 for displaying the player icon in scaledrelationship in the virtual space 30. An acceptable computer is a CompaqPentium PC. Other computers using a Pentium processor, a Pentium IIprocessor, or other suitable processors would also be acceptable. Inother words, the player icon 32 typically will be positioned in thecomputer-generated virtual space 30 at the x, y, z coordinatescorresponding to the player's actual location in the physical space 12.However, it will be appreciated that the player icon may be placed inthe virtual space at location(s) other than those corresponding to theplayer's location in physical space.

As the player 36 changes location within the physical space 12, theplayer icon 32 is repositioned accordingly in the virtual space 30. Therepositioning is taken into account in an updated view fed to thedisplay 28. In addition, past positions of the player icon 32 may berepresented in the display. For example, “ghosts”, reduced brightnessimages of the player icon, may be displayed at locations where theplayer has recently been. This gives an indication of the recent path ofmotion of the player. Alternatively, the recent motion of the player maybe indicated by a line trace which fades in intensity over time. Suchindications may be used only for certain parts of a player's motion—forexample only for jumps or leaps.

The computer 22 may retain a record of some or all of the data regardingthe player's position on a data storage device such as hard disk or awriteable optical disk. This retained data may be in raw form, with therecord containing the actual positions of the player at given times.Alternatively, the data may be processed before being recorded, forexample with the accelerations of the player at various times beingrecorded.

To create tasks that induce the player 36 to undertake certainmovements, a protagonist icon 34 is displayed in the computer-generatedvirtual space 30 by the computer software. The protagonist icon 34serves to induce, prompt and lead the player 36 through various tasks,such as testing and training protocols in an interactive game-likeformat that allows the assessment and quantification of movement andagility skills related to actual distance traveled and elapsed time inthe physical space 12 to provide physics-based vector and scalarinformation.

The protagonist icon 34 may be interactive with the player 36. Forexample, an interception task allows the player icon 32 and theprotagonist icon 34 to interact until the two icons occupy the same or asimilar location, whence the task ends. An evasion task, on the otherhand, involves interaction of the player icon 32 and the protagonisticon 34 until the two icons have attained a predetermined separation. Asused herein the protagonist icon is the graphic representation withwhich the player interacts, and defines the objective of the task. Othercollision-based icons, such as obstacles, barriers, walls and the likemay embellish the task, but are generally secondary to the objectivebeing defined by the protagonist.

The protagonist icon 34 may have varying attributes. For example, theprotagonist icon may be dynamic, rather than stationary, in that itslocation changes with time under the control of the software therebyrequiring the player to determine an ever changing interception orevasion path to complete the task.

Further, the protagonist icon can be intelligent, programmed to be awareof the player's position in the computer-generated virtual space 30 andto intercept or evade according to the objectives of the task. Suchintelligent protagonist icons are capable of making course correctionchanges in response to changes in the position of the player icon 32 inmuch the same manner as conventional video games wherein the targets areresponsive to the icon under the player's control, the difference beingthat the player's icon does correspond to the player's actual positionin a defined physical space.

The foregoing provides a system for assessing movement skills andagility skills. Movement skills are generally characterized in terms ofthe shortest time to achieve the distance objective. They can be furthercharacterized by direction of movement with feedback, quantification andassessment being provided in absolute units, i.e., distance/time unit,or as a game score indicative of the player's movement capabilitiesrelated to physics-based information including speed, velocity,acceleration, deceleration and displacement. Agility is generallycharacterized as the ability to quickly and efficiently change bodyposition and direction while undertaking specific movement patterns. Theresults also are reported in absolute units, with success determined bythe elapsed time to complete the task.

An exemplary software flow chart for the foregoing tasks is shown inFIGS. 6 and 7. At the start 80 of the assessment, the player is promptedto Define Protagonist(s) 82. The player may select the intelligencelevel, number, speed and size of the protagonists to reside in theselected routine. Thereafter the player is prompted to DefineObstacle(s) 84, i.e., static vs. dynamic, number, speed, size and shape.The player is then prompted to Define Objective(s) 86, i.e., avoidanceor interception, scoring parameters, and goals, to complete the setuproutine.

To start the task routine, the player is prompted to a starting positionfor the task and upon reaching this position, the protagonist(s) and theobstacle(s) for the task are generated on the display. The protagonistmoves on the display in step 90, in a trajectory dependent on the setupdefinition. For an interception routine, the player moves in a pathwhich the player determines will result in the earliest interceptionpoint with the protagonist in accordance with the player's ability.During player movement, the player icon is generated and continuallyupdated, in scaled translation in the virtual space to the player'sinstantaneous position in the defined physical space. Movement continuesuntil player contact with the protagonist icon in step 92, resulting ininterception in step 94, or until the protagonist contacts a boundary ofthe virtual space corresponding to the boundary of the defined physicalspace, 96. In the former case, if interception has occurred, a newprotagonist appears on a new trajectory, 97. The player icon's positionis recorded, 98, the velocity vectors calculated and recorded, and ascore or assessment noted on the display. The system then determines ifthe task objectives have been met, 100, and for a single task, the finalscore is computed and displayed, 102, as well as information related totime and distance traveled in completing the task, and the session ends,104.

In the event the player does not intercept the protagonist icon prior tothe latter contacting a virtual space boundary corresponding to theboundary on the defined physical space, the direction of the protagonistis changed dependent on the setup definition, and the pursuit of theprotagonist by the player continues as set forth above.

Concurrently with the player pursuit, in the event that obstacles havebeen selected in the setup definition, the same are displayed, 110, andthe player must undertake a movement path to avoid these obstacles. Fora single segment task, if the player contacts the obstacle, 112, theobstacle is highlighted, 114, and the routine is completed and scored asdescribed above. In the event a moving obstacle was selected in thesetup definition, if the obstacle strikes a boundary, 116, theobstacle's direction is changed, 118, and the task continues.

For a multiple segment task, if the obstacle is contacted, theprotagonist's direction changes and the movements continue. Similarly,upon interception for a multiple segment task, a new protagonisttrajectory is initiated and the obstacles also may be reoriented. Theroutine then continues until the objectives of the task have been metand the session completed.

The tasks are structured to require the player to move forward,backward, left and right, and optionally vertically. The player'smovement is quantified as to distance and direction dependent on thesampling rate and the update rate of the system. For each samplingperiod, the change in position is calculated. At the end of the session,these samples are totaled and displayed for the various movementvectors.

For an avoidance task wherein the objective of the session is to avoid aprotagonist seeking to intercept the player, the aforementioned isappropriately altered. Thus if the player is intercepted by theprotagonist, the session ends for a single segment task and the time anddistance related information is calculated and displayed. For multiplesegment tasks, the protagonist trajectory has a new origin and thesession continues for the defined task until completed or terminated.

An example of a functional movement skills test is illustrated in FIG. 3by reference to a standard three hop test. Therein the player 36 orpatient stands on one leg and performs three consecutive hops as far aspossible and lands on the same foot. In this instance the player icon 32is displayed at the center of the rear portion of the computer-generatedvirtual space 30, a position in scaled translation to the position ofthe player 36 in the defined physical space 12. Three hoops 50,protagonist icons, appear on the display indicating the sequence of hopsthe player should execute. The space of the hoops may be arbitrarilyspaced, or may be intelligent, based on standard percentile data forsuch tests, or on the best or average past performances of the player.

In one embodiment, the player 36 is prompted to the starting position52.

When the player reaches such position, the three hoops 50 appearrepresenting the 50th percentile hop distances for the player'sclassification, and after a slight delay the first hoop is highlightedindicating the start of the test. The player then executes the first hopwith the player's movement toward the first hoop being depicted inessentially real-time on the display. When the player lands aftercompletion of the first hop this position is noted and stored on thedisplay until completion of the test and the second hoop and third hoopare sequentially highlighted as set forth above. At the end of the threehops, the player's distances will be displayed with reference tonormative data.

A test for agility assessment is illustrated in FIG. 4 for a SEMOAgility Test wherein the generated virtual space 30 is generally withinthe confines of a basketball free throw lane. Four cones 60, 62, 64, 66are the protagonist icons. As in the movement skills test above, theplayer 36 is prompted to a starting position 68 at the lower rightcorner. When the player 36 reaches the starting position in the definedphysical space the left lower cone 62 is highlighted and the player sidesteps leftward thereto while facing the display. After clearing thevicinity of cone 62, the fourth cone 66, diagonally across at the frontof the virtual space 30 is highlighted and the player moves toward andcircles around cone 66. Thereafter the player moves toward the startingcone 60 and circles the same and then moves to a highlighted thirdvirtual cone 64. After circling the cone 64, cone 66 is highlighted andthe player moves toward and circles the cone 66 and then side steps tothe starting position 68 to complete the test. In the conventional test,the elapsed time from start to finish is used as the test score. Withthe present invention, however, each leg of the test can be individuallyreported, as well as forward, backward and side to side movementcapabilities.

As will be apparent from the above embodiment, the system provides aunique measurement of the player's visual observation and assessesskills in a sport simulation wherein the player is required to interceptor avoid the protagonist based on visual observation of the constantlychanging spatial relationship with the protagonist. Additionally,excursions in the Y-plane can be quantified during movement as a measureof an optimal stance of the player.

The foregoing and other capabilities of the system are furtherillustrated by reference to FIG. 5. Therein, the task is to intercepttargets 70, 71 emanating from a source 72 and traveling in straight linetrajectories T1, T2. The generated virtual space 30 displays a pluralityof obstacles 74 which the player must avoid in establishing aninterception path with the target 70. The player assumes in the definedphysical space a position which is represented on the generated virtualspace as position P (X1, Y1, Z1) in accurately scaled translationtherewith. As the target 70 proceeds along trajectory T1, the playermoves along a personally determined path in the physical space which isindicated by the dashed lines in the virtual space to achieve aninterception site coincident with the instantaneous coordinates of thetarget 70, signaling a successful completion of the first task. Thisachievement prompts the second target 71 to emanate from the sourcealong trajectory T2. In order to achieve an intercept position for thistask, the player is required to select a movement path which will avoidcontact or collision with virtual obstacle 74. Thus, within thecapabilities of the player, a path shown by the dashed lines is executedin the defined physical space and continually updated and displayed inthe virtual space as the player intercepts the protagonist target atposition P(X3, Y3, Z3) signaling completion of the second task. Theassessment continues in accordance with the parameters selected for thesession, at the end of which the player receives feedback indicative ofsuccess, i.e., scores or critical assessment based on the distance,elapsed time for various vectors of movement.

Another protocol is a back and forth hop test. Therein, the task is tohop back and forth on one leg over a virtual barrier displayed in thecomputer-generated virtual space. The relevant information uponcompletion of the session would be the amplitude measured on each hopwhich indicates obtaining a height sufficient to clear the virtualbarrier. Additionally, the magnitude of limb oscillations experiencedupon landing could be assessed. In this regard, the protocol may onlymeasure the vertical distance achieved in a single or multiple verticaljump.

The aforementioned system accurately, and in essentially real time,measures the absolute three dimensional displacements over time of thebody's center of gravity when the sensor marker is appropriately locatedon the player's mass center. Measuring absolute displacements in thevertical plane as well as the horizontal plane enables assessment ofboth movement skills and movement efficiency.

In many sports, it is considered desirable for the player to maintain aconsistent elevation of his center of gravity above the playing surface.Observation of excursions of the player's body center of gravity in thefore-aft (Z) during execution of tests requiring solely lateralmovements (X) would be considered inefficient. For example,displacements in the player's vertical (Y) plane during horizontalmovements that exceed certain preestablished parameters could beindicative of movement inefficiencies.

In a further protocol using this information, the protagonist iconfunctions as an aerobics instructor directing the player through aseries of aerobic routines. The system can also serve as an objectivephysiological indicator of physical activity or work rate during freebody movement in essentially real time. Such information provides threebenefits: (1) enables interactive, computer modulation of the workoutsession by providing custom movement cues in response to the player'scurrent level of physical activity; (2) represents a valid and uniquecriteria to progress the player in his training program; and (3)provides immediate, objective feedback during training for motivation,safety and optimized training. Such immediate, objective feedback ofphysical activity is generally missing in current aerobics programs,particularly in unsupervised home programs.

Quantification of Performance-Related Parameters

In certain embodiments of the present invention, performance-relatedphysical activity parameters related to movement (indicia derived frommovement parameters), including calories burned, are monitored andquantified. The repetitive drudgery of conventional stationary exerciseequipment that currently measures calories, heart rate, etc. is replacedby the excitement of three-dimensional movement in interactive responseto virtual reality challenges presented on the monitor of the inventivesystem. Excitement is achieved in part by the scaling transformationachieved by the present invention, through which positional changes bythe user moving in real space are represented in scaled relationship inthe virtual world presented on the monitor.

Performance-related parameters measured and/or quantified by variousembodiments of the present invention include those related to (a)determining and training a user's optimal dynamic posture; (b) therelationship between heart rate and physical activity; (c) quantifyingquickness, i.e., acceleration and deceleration; and (d) and quantifyingenergy expenditure during free ranging activities.

It is especially significant that the user's energy expenditure may beexpressed as calories burned, inasmuch as this is a parameter of primaryconcern to many exercisers. One advantage of the present system is thata variety of environments in the virtual world displayed on the monitorcan prompt any desired type and intensity of physical activity,achieving activity and energy expenditure goals in an ever-changing andchallenging environment, so that the user looks forward to, rather thandreads, exercise, testing, or therapy sessions.

Measurement of motion (movement in three planes) is used to quantifywork and energy expenditure. Movement-related quantities (movementparameters) such as force, acceleration, work and power, defined below,are dependent on the rate of change of more elementary quantities suchas body position and velocity (the latter of which is also a movementparameter). The energy expenditure of an individual is related to themovement of the individual while performing the invention protocols.

The concept that a complex motion can be considered as a combination ofsimple bilateral movements in any of three directions is convenientsince this approach allows focus on elementary movements with subsequentadding of the effects of these simple components. Such concept relatesto the ability to monitor continuously the movement of the individual tomeasure the resultant energy expenditure.

The ability of this embodiment to accurately measure a subject'smovement rests on being able to determine his or her position andvelocity at arbitrary points of time. For a given point in time, aposition is measured directly. The sampling rate of the position of theindividual or player 36 is sufficiently fast to allow accuratemeasurements to be made at very closely spaced intervals of time. Byknowing an individual's position at arbitrary points along its path thevelocity can be calculated.

In the present embodiment, positions can be used to determine velocityalong a movement path: given the position of the individual at variousinstances of time, the embodiment can obtain the velocity in severalways. One method is to choose a point and calculate its velocity asbeing the result of dividing the distance between it and the next pointby the time difference associated with those points. This is known as afinite difference approximation to the true velocity. For small spacingbetween points, it is highly accurate.

If D is the distance between consecutive points and T equal the timeperiod to travel the distance D, then the velocity V is given by thefollowing rate of change formula

V=D/T,

where V has the units of meters per second, m/s.

In three dimensional space, D is computed by taking the change in eachof the separate bilateral directions into account. If dX, dY, and dZrepresents the positional changes between the successive bilateraldirections, then the distance D is given by the following formula

D=sqrt(dX*dX+dY*dY+dZ*dZ),

where “sqrt” represents the square root operation. The velocity can belabeled positive for one direction along a path and negative for theopposite direction. This is, of course, true for each of the bilateraldirections separately.

This finite difference approximation procedure can also be used tocalculate the acceleration of the object along the path. This isaccomplished by taking the change in velocity between two consecutivepoints and dividing by the time interval between points. This gives anapproximation to the acceleration A of the object which is expressed asa rate of change with respect to time as follows

A=dV/T,

where dV is the change in velocity and T is the time interval.Acceleration is expressed in terms of meters per second per second. Theaccuracy of this approximation to the acceleration is dependent on usingsufficiently small intervals between points.

As an alternate to using smaller position increments to improveaccuracy, more accurate finite difference procedures may be employed.This embodiment obtains positional data with accuracy within a fewcentimeters over time intervals of approximately 0.020 seconds, so thaterrors are assumed to be negligible.

In contrast to the finite difference approach, the positional data couldbe fitted by spline curves and treated as continuous curves. Thevelocity at any point would be related to the tangent to theindividual's path using derivative procedures of standard calculus. Thiswould give a continuous curve for the velocity from which acorresponding curve could be obtained for the acceleration of theindividual.

It will be appreciated that other methods of modeling may be used toprovide accurate estimations of velocity and acceleration.

In any case, the determination of the individual's acceleration providesa knowledge of the force F it experiences. The force is related to themass M of the individual, given in kilograms, and acceleration, by theformula

F=M*A.

This is a resultant formula combining all three components of force andacceleration, one component for each of the three bilateral directions.The international standard of force is a newton which is equivalent to akilogram mass undergoing an acceleration of one meter per second persecond. This embodiment requires that the individual enter body weightprior to playing. (Body weight is related to mass by the acceleration ofgravity.)

The effect of each component can be considered separately in analyzingan individual's movement. This is easily illustrated by recognizing thatan individual moving horizontally will be accelerated downward due togravity even as he or she is being decelerated horizontally by air drag.The effects of forces can be treated separately or as an aggregate. Thisallows one the option to isolate effects or lump effects together. Thisoption provides flexibility in analysis.

Energy and work may be measured in the present invention. The energyexpended by an individual in the inventive system can be derived fromwork. The mechanical work is calculated by multiplying the force actingon an individual by the distances that the individual moves while underthe action of force. The expression for work (W) is given by

W=F*d.

The unit of work is a joule, which is equivalent to a newton-meter.

Power P is the rate of work production and is given by the followingformula

P=W/T

The standard unit for power is the watt and it represents one joule ofwork produced per second.

Different individuals performing the same activity expend differentamounts of heat due to differences in body mass, gender, and otherfactors. As indicated above, mechanical work done in an activity isdetermined in the present invention system by monitoring motionparameters associated with that activity. Total energy expenditure canbe derived from known work-to-calories ratios.

A protocol called “Dynamic Posture” represents the athletic stancemaintained during sport specific activity that maximizes a player'sreadiness for a specific task. Examples are the slight crouches or“ready” position of a soccer goalie or a football linebacker.

Testing or training of dynamic posture is achieved by having the userinitially assume the desired position and then tracking, in essentiallyreal-time, displacements in the Y (vertical) plane during interactiveprotocols. Such Y plane displacements accurately reflect verticalfluctuations of that point on the body on which the reflective marker isplaced, for example, the hipline, which is often referred to as theCenter of Gravity (CG) point.

It may be desirable to determine dynamic posture and train an athlete inobtaining optimal dynamic posture. The optimal dynamic posture duringsport-specific activities is determined as follows:

A retro-reflective marker is mounted at the athlete's CG point.

The invention's computer 22 measures in real-time vertical displacementsof the athlete's CG (Y-plane excursions) as he responds to interactive,sport-specific protocols.

The invention's computer 22 calculates in essentially real-time theathlete's movement velocities and/or accelerations during performance ofsport-specific protocols.

The invention calculates the athlete's most efficient dynamic posturedefined as that CG elevation that produces maximum velocities and/oraccelerations/decelerations for the athlete in the sports-specificprotocols.

The invention provides numerical and graphical feedback of results.

Once the optimal dynamic posture is determined, training optimal dynamicposture is achieved by the following steps:

A retro-reflective marker is mounted at the athlete's CG point.

The athlete 36 assumes the dynamic posture that he or she wishes totrain.

The invention is initialized for this CG position.

The invention provides varying interactive movement challenges oversport-specific distances and directions, including unplanned movements,

Y-plane excursions from the optimal dynamic posture that exceed thepre-set threshold or window will generate real-time feedback of suchviolations for the user.

The invention provides real-time feedback of compliance with the desireddynamic posture during performance of the protocols.

The invention uses unplanned, interactive game-like movement challengesrequiring sport-specific responses. The participant will move mosteffectively during stopping, starting and cutting activities if heassumes and maintains his optimum Center of Gravity (CG) elevation.Additional movement efficiencies are achieved by the player byminimizing CG elevation excursions. The invention is capable of trackingin essentially real-time, the participant's CG elevation by monitoring Yplane displacements. During the training phase, the participant will beprovided with real-time feedback of any Y plane excursions exceedingtargeted ranges.

The relationship between heart rate and physical activity of the subjectduring performance of the protocols is also quantified by the presentinvention. Heart rate is measured by a commercially available wireless(telemetry) device 36A (FIG. 2) in essentially real-time. Conventionalcardiovascular exercise equipment attempts to predict caloricexpenditure from exercise heart rate. Real time monitoring of heart rateis an attempt to infer the users' level of physical activity. However,as heart rate is affected by factors other than physical activity suchas stress, ambient temperature and type of muscular contraction, theratio or relationship between heart rate and energy expended may beenlightening to the coach, athlete or clinician. For example, physicaltraining lowers the heart rate at which tasks of a given energy cost areperformed.

Prior art applications have attempted to measure these two parameterssimultaneously in an attempt to validate one of the measurementconstructs as a measure of physical activity. In all such cases though,such measurements were not in real-time; they were recorded over timeand did not employ position tracking means nor involve interactiveprotocols used in the inventive system.

In another aspect of the invention, simultaneous assessment andmodulation of physical activity and heart rate is achieved as follows:

The subject 36 places a retro-reflective marker at his CG point.

A wireless heart-rate monitor 36A (FIG. 2) is worn on the subject 36,the monitor 36A in communication in real-time with the computer 22.

Subject 36 enters desired target heart-rate range. (This step isoptional.)

The invention provides interactive, functional planned and unplannedmovement challenges (protocols) over varying distances and directions.

The invention provides real-time feedback of compliance with selectedheart-rate zone during performance of these protocols.

The invention provides a graphical summary of the relationship orcorrelation between heart-rate at each moment of time and free-bodyphysical activity.

The present invention includes assessment and quantification of movementskills such as accelerations and decelerations during unplanned movementprotocols over sport-specific distances. Quantification of bi-lateralvector accelerations and decelerations (how well a subject 36 moves leftand right) are achieved as follows:

A retro-reflective marker is mounted at the athlete's CG point,

The invention tracks at sufficient sampling rate the athlete's movementin three degrees of freedom during his performance of sport-specificprotocols, including unplanned movements over various vector distances,

The invention calculates in essentially real-time the athlete's movementaccelerations and decelerations,

The invention categorizes each movement leg to a particular vector,

The invention provides numerical and graphical feedback of bi-lateralperformance.

Quantification of the intensity of free-ranging physical activity asexpressed in kilocalories per minute, and the total energy expended, isderived from movement data collected as the subject moves in response toprompts from the monitor, personal data such as weight inputted by thesubject, and conventional conversion formulae.

During performance of the above protocols, the inventive system canmeasure the intensity, i.e., strenuousness or energy cost of physicalactivity during free ranging (functional) activities, expressed incalories per minute, distance traveled per unit of time.

Energy expenditure can be derived from the subject's movement dataduring performance of free-ranging activities. Well known laboratoryinstrumentation can be employed to ascertain the coefficient orconversion factor needed to convert work or power or distance derivedfrom the movement data to calories expended. Oxygen uptake, expressed inmilliliters per kilogram per minute can determine the caloricexpenditure of physical activity and is considered the “gold standard”or reference when evaluating alternative measures of physical activity.The most precise laboratory means to determine oxygen uptake is throughdirect gas analysis, which would be performed on representative subjectpopulations during their execution of the invention's protocols with ametabolic cart, which directly measures the amount of oxygen consumed.Such populations would be categorized based on age, gender and weight.

The software flow chart for the tasks of an illustrative embodiment isshown in FIGS. 8 and 9. After the start 80 of the assessment, the useris prompted to DEFINE PLAYER ICON (81). This is when the player's bodyweight, sex, etc., other information necessary to calculate calories, isentered. The player is prompted to Define Protagonists 82. The playermay select the intelligence level, number, speed and size of theprotagonists to reside in the selected routine. Thereafter the player isprompted to Define Obstacles 84, i.e., static vs. dynamic, number,speed, size and shape. The player is then prompted to Define Objectives86, i.e., avoidance or interception, scoring parameters, and goals, tocomplete the setup routine. As part of DEFINE OBJECTIVES (86), theplayers 3-D path boundaries should be programmed, the reference frame ofplay, i.e., 1st person, 3rd person. The player is then prompted by PATHVIOLATION (86A). If yes then provide audio/visual cues alarms and recordplayer's icon change in position else just record player's icon changein position. The OBJECTIVES MET decision block should point here if NO.

To start the task routine, the player is prompted to a starting positionfor the task and upon reaching this position, the protagonist(s) and theobstacle(s) for the task are generated on the display. The protagonistmoves on the display, 90, in a trajectory dependent on the setupdefinition. For an interception routine, the player moves in a pathwhich the player determines will result in the earliest interceptionpoint with the protagonist in accordance with the player's ability.During player movement, the player icon is generated, and continuallyupdated, in scaled translation in the virtual space to the player'sinstantaneous position in the defined physical space. Movement continuesuntil player contact, 92, and interception, 94, or until the protagonistcontacts a boundary of the virtual space corresponding to the boundaryof the defined physical space, 96. In the former case, if interceptionhas occurred, a new protagonist appears on a new trajectory, 97. Theplayer icon's position is recorded, 98, the velocity vectors calculatedand recorded, and a score of assessment noted on the display. The systemthen determines if the task objectives have been met, 100, and for asingle task, the final score is computed and displayed, 102, andcalories burned in calculated, as well as information related to timeand distance traveled in completing the task, and the session ends, 104.

In the event the player does not intercept the protagonist icon prior tothe latter contacting a virtual space boundary corresponding to theboundary on the defined physical space, the direction of the protagonistis changed dependent on the setup definition, and the pursuit of theprotagonist by the player continues as set forth above.

Concurrently with the player pursuit, in the event that obstacles havebeen selected in the setup definition, the same are displayed, 110, andthe player must undertake a movement path to avoid these obstacles. Fora single segment task, if the player contacts the obstacle, 112, theobstacle is highlighted, 114, and the routine is completed and scored asdescribed above. In the event a moving obstacle was selected in thesetup definition, if the obstacle strikes a boundary, 116, theobstacle's direction is changed, 118, and the task continues.

For a multiple segment task, if the obstacle is contacted, theprotagonist's direction changes and the movements continue. Similarly,upon interception for a multiple segment task, a new protagonisttrajectory is initiated and the obstacles also may be reoriented. Theroutine then continues until the objectives of the task have been met,and the session completed.

The tasks are structured to require the player to move forward,backward, left and right, and optionally vertically. The player'smovement is quantified as to distance and direction dependent on thesampling rate and the update rate of the system. For each samplingperiod, the change in position is calculated. At the end of the session,these samples are totaled and displayed for the various movementvectors.

For an avoidance task wherein the objective of the session is to avoid aprotagonist seeking to intercept the player, the aforementioned isappropriately altered. Thus if the player is intercepted by theprotagonist, the session ends for a single segment task and the time anddistance related information is calculated and displayed. For multiplesegment tasks, the protagonist trajectory has a new origin and thesession continues for the defined task until completed or terminated.

Performance Measurement Constructs

The present invention provides a unique and sophisticated computersports simulator faithfully replicating the ever-changing interactionbetween offensive and defensive opponents. This fidelity with actualcompetition enables a global and valid assessment of an offensive ordefensive player's functional, sport-specific performance capabilities.Such assessment may include use of indicia that are or are derived frommovement parameter(s). Among these indicia derived from movementparameter(s) are several novel and interrelated measurement constructswhich have been derived and rendered operable by specializedposition-sensing hardware and interactive software protocols.

Feedback may be provided to the player regarding the measurementconstructs. This feedback may take many forms. The feedback may beprovided during the interactive session, with there being some effect inthe virtual space (and the view) that is a function of one or more ofthe constructs, for example. Alternatively or in addition, feedback maybe provided after the end of one or more interactive sessions.

One of the measurement constructs of the present invention isCompliance, a global measure of the player's core defensive skills isthe ability of the player to maintain a synchronous relationship withthe dynamic cues that are often expressed as an offensive virtualopponent. The ability to faithfully maintain a synchronous relationshipwith the virtual opponent is expressed either as compliance (variance ordeviation from a perfect synchronous relationship with the virtualopponent) and/or as absolute performance measures of the player'svelocity, acceleration and power. An integral component of such asynchronous relationship is the player's ability to effectively changeposition, i.e., to cut, etc. as discussed below. Referring to FIG. 10,Compliance may be determined as follows:

A beacon, a component of the tracking system, is worn at the Player'swaist.

At Position A software scaling parameters make the virtual opponent 210,coordinates in the virtual environment equivalent to the player's 212coordinates in the physical environment.

The system's video displays the virtual opponent's movement alongPath1(x,y,z,t) 214 as a function of dimensions X, Y and Z, and time(x,y,z,t) to a virtual Position B 216.

In response, the Player moves along Path 2 (x,y,z,t) 218 to a nearequivalent physical Position C 220. The Player's objective is to moveefficiently along the same path in the physical environment from startto finish, as does the avatar in the virtual environment. However, sincethe virtual opponent typically moves along random paths and the Playeris generally not as mobile as the virtual opponent, the player'smovement path usually has some position error measured at every sampleinterval.

The system calculates at each sampling interval the Player's newposition, velocity, acceleration, and power, and determines the Player'slevel of compliance characterized as measured deviations from theoriginal virtual opponent 210-Player 212 spacing at position A.

The system provides real time numerical and graphical feedback of thecalculations of part e.

Another measurement construct of the present invention is Opportunity—aquantification of the player's ability to create an asynchronousmovement event when in an offensive role. The player's ability toexecute abrupt changes (to cut) in his or her movement vector direction,expressed in the aforementioned absolute measures of performance, is oneof the parameters indicative of the player's ability to create thisasynchronous movement event. Referring to FIG. 11, Opportunity may bedetermined as follows:

A beacon, a component of the optical tracking system, is worn at thePlayer's waist.

At Position A, software scaling parameters make the virtual opponent222, coordinates in the virtual environment equivalent to the player's224 coordinates in the physical environment.

The Player moves along Path2(x,y,z,t) 226 to a physical Position C 228The Player's objective is to maximize his/her movement skills in orderto elude the virtual opponent 222.

In response, the system's video displays the virtual opponent's movementalong Path1(x,y,z,t) 230 to an equivalent virtual Position B 232. Thevirtual opponent's movement characteristics are programmable andmodulated over time in response to the Player's performance.

The system calculates at each sampling interval the Player's newposition velocity, acceleration, and power, and determines the momentthe Player has created sufficient opportunity to abruptly redirecthis/her movement along Path3(x,y,z,t) 234 to intersect the virtualopponent's x-y plane to elude and avoid collision with the virtualopponent.

The system provides real time numerical and graphical feedback of thecalculations of part e.

A number of performance components are essential to successfullyexecuting the two aforementioned global roles. Accordingly the systemassesses the following performance constructs or components: DynamicReaction Time, Dynamic Phase Lag, First Step Quickness, and DynamicReactive Bounding, Dynamic Sports Posture, Functional Cardio-respiratoryStatus, Dynamic Reactive Cutting. These constructs are explained indetail below.

Dynamic Reaction Time is a novel measure of the player's ability toreact correctly and quickly in response to cuing that prompts a sportspecific response from the player. It is the elapsed time from themoment the virtual opponent attempts to improve its position (from thepresentation of the first indicating stimuli) to the player's initialcorrect movement to restore a synchronous relationship (player's initialmovement along the correct vector path).

Dynamic Reaction Time is a measurement of ability to respond tocontinually changing, unpredictable stimuli, i.e., the constant faking,staccato movements and strategizing that characterizes game play. Thepresent invention uniquely measures this capability in contrast tosystems providing only static cues which do not provide for continualmovement tracking.

Dynamic Reaction Time is comprised of four distinct phases: theperception of a visual and/or audio cue, the interpretation of thevisual and/or audio cue, appropriate neuromuscular activation, andmusculoskeletal force production resulting in physical movement. It isimportant to note that Dynamic Reaction Time, which is specificallymeasured in this protocol, is a separate and distinct factor from rateand efficiency of actual movement which are dependent on muscular power,joint integrity, movement strategy and agility factors. Function relatedto these physiological components is tested in other protocols includingPhase Lag and First Step Quickness.

Faced with the offensive player's attempt to create an asynchronousevent, the defensive player must typically respond within fractions of asecond to relevant dynamic cues if the defensive player is to establishor maintain the desired synchronous relationship. With such minimumresponse time, and low tolerance for error, the defensive player'sinitial response must typically be the correct one. The player mustcontinually react to and repeatedly alter direction and/or velocityduring a period of continuous movement. Any significant response lag orvariance in relative velocity and/or movement direction between theplayer and virtual opponent places the player irrecoverably out ofposition.

Relevant testing must provide for the many different paths of movementby the defensive player that can satisfy a cue or stimulus. The stimulusmay prompt movement side to side (the X translation), fore and aft (theZ translation) or up or down (the Y translation). In many instances, theappropriate response may simply involve a twist or torque of theplayer's body, which is a measure of the orientation, i.e., a yaw, pitchor roll.

Referring to FIG. 12, Dynamic Reaction Time may be determined asfollows:

A beacon, a component of the optical tracking system, is worn at thePlayer's waist.

At Position A, software scaling parameters make the virtual opponent236, coordinates in the virtual environment equivalent to the player's238 coordinates in the physical environment.

The system's video displays the virtual opponent's movement alongPath1(x,y,z,t) 240 to a virtual Position B 242.

In response, the Player moves along Path2(x,y,z,t) 244 to a nearequivalent physical Position C 246. The Player's objective is to moveefficiently along the same path in the physical environment from startto finish as does the virtual opponent in the virtual environment.However, since the virtual opponent typically moves along random pathsand the Player is generally not as mobile as the virtual opponent, theplayer's movement path usually has some position error measured at everysample interval.

Once the virtual opponent reaches Position B 242, it immediately changesdirection and follows Path3(x,y,z,t) 248 to a virtual Position D 250.The Dynamic Reaction Timer is started after the virtual opponent's x, y,or z velocity component of movement reaches zero at Position B 242 andits movement along Path3(x,y,z,t) 248 is initiated.

The Player perceives and responds to the virtual opponent's new movementpath by moving along Path4(x,y,z,t) 252 with intentions to comply tovirtual opponent's new movement path. The Dynamic Reaction Timer isstopped at the instant the Player's x, y, or z velocity component ofmovement reaches zero at Position C 246 and his/her movement isredirected along the correct Path4(x,y,z,t) 252.

The system calculates at each sampling interval the Player's newposition velocity, acceleration, and power.

The system provides real time numerical and graphical feedback of thecalculations of part g and the Dynamic Reaction Time.

Dynamic Phase Lag is defined as the elapsed time that the player is “outof phase” with the cuing that evokes a sport specific response from theplayer. It is the elapsed time from the end of Dynamic Reaction Time toactual restoration of a synchronous relationship by the player with thevirtual opponent. In sports vernacular, it is the time required by theplayer to “recover” after being “out-of-position” while attempting toguard his opponent.

Referring to FIG. 13, Dynamic Phase Lag may be determined as follows:

A beacon, a component of the optical tracking system, is worn at thePlayer's waist.

At Position A, software scaling parameters make the virtual opponent254, coordinates in the virtual environment equivalent to the player's256 coordinates in the physical environment.

The system's video displays the virtual opponent's movement alongPath1(x,y,z,t) 258 to a virtual Position B 260.

In response, the Player moves along Path2(x,y,z,t) 262 to a nearequivalent physical Position C 264. The Player's objective is to moveefficiently along the same path in the physical environment from startto finish as does the Avatar in the virtual environment. However, sincethe virtual opponent typically moves along random paths and the Playeris generally not as mobile as the virtual opponent 254, the player'smovement path usually has some position error measured at every sampleinterval.

Once the virtual opponent reaches Position B 260, it immediately changesdirection and follows Path3(x,y,z,t) 266 to a virtual Position D 268.

The Player perceives and responds to the virtual opponent's new movementpath by moving along Path4(x,y,z,t) 270. The Phase Lag Timer is startedat the instant the Player's x, y, or z velocity component of movementreaches zero at Position C 264 and his/her movement is directed alongthe correct Path4(x,y,z,t) 270 to position E 272.

When the Player's Position E finally coincides or passes within anacceptable percentage of error measured with respect to the virtualopponent's at Position D 268 the Phase Lag Timer is stopped.

The system calculates at each sampling interval the Player's newposition velocity, acceleration, and power.

The system provides real time numerical and graphical feedback of thecalculations of part h and the Phase Lag Time.

First Step Quickness may be measured as the player attempts to establishor restore a synchronous relationship with the offensive virtualopponent. First step quickness is equally important for creating anasynchronous movement event for an offensive player.

Acceleration is defined as the rate of increase of velocity over timeand is a vector quantity In sports vernacular, an athlete with firststep quickness has the ability to accelerate rapidly from rest, anathlete with speed has the ability to reach a high velocity over longerdistances. One of the most valued attributes of a successful athlete inmost sports is first step quickness.

This novel measurement construct purports that acceleration is a moresensitive measure of “quickness” over short, sport-specific movementdistances than is average velocity or speed. This is especially truesince a realistic simulation of sports challenges, which are highlyvariable in distance, would not be dependent upon fixed start and endpositions. A second reason that the measurement of acceleration oversport-specific distances appears to be a more sensitive and reliablemeasure is that peak accelerations are reached over shorter distances,as little as one or two steps.

First step quickness can be applied to both static and dynamicsituations. Static applications include quickness related to basestealing. Truly sports relevant quickness means that the athlete is ableto rapidly change his movement pattern and accelerate in a new directiontowards his goal. This type of quickness is embodied by Michael Jordan'sskill in driving to the basket. After making a series of misleadingmovement cues, Jordan is able to make a rapid, powerful drive to thebasket. The success of this drive lies in his first step quickness.Valid measures of this sports skill must incorporate the detection andquantifying of changes in movement based upon preceding movement.Because the vector distances are so abbreviated and the player istypically already under movement prior to “exploding”, acceleration,power and/or peak velocity are assumed to be the most valid measures ofsuch performance. Measures of speed or velocity over such distances maynot be reliable, and at best, are far less sensitive indicators.

Numerous tools are available to measure the athlete's average velocitybetween two points, the most commonly employed tool being a stopwatch.By knowing the time required to travel the distance between a fixedstart and end position, i.e., a known distance and direction, theathlete's average velocity can be accurately calculated. But just as anautomobile's zero to sixty-mph time, a measure of acceleration, is moremeaningful to many car aficionados than its top speed, an averagevelocity measure does not satisfy interest in quantifying the athlete'sfirst step quickness. Any sport valid test of 1st step quickness mustreplicate the challenges the athlete will actually face in competition.

In situations where the athlete's movement is over short, sport-specificdistances that are not fixed start and stop positions, the attempt tocompare velocities in various vectors of unequal distance is subject toconsiderable error. For example, comparison of bilateral vectorvelocities achieved over different distances will be inherentlyunreliable in that the athlete, given a greater distance, will achievehigher velocities. Conventional testing means, i.e., without continualtracking of the player, can not determine peak velocities, only averagevelocities.

Only by continuous, high-speed tracking of the athlete's positionalchanges in three planes of movement can peak velocity, acceleration,and/or power be accurately measured. For accurate assessment ofbilateral performance, the measurement of power, proportional to theproduct of velocity and acceleration, provides a practical means fornormalizing performance data to compensate for unequal distances overvarying directions since peak accelerations are achieved within a fewsteps, well within a sport-specific playing area First Step Quicknessmay be determined as follows.

Referring to FIG. 14,

-   -   a) A beacon, a component of the optical tracking system, is worn        at the Player's waist.    -   b) At Position A, software scaling parameters make the virtual        opponent 274 coordinates in the virtual environment equivalent        to the player's 276 coordinates in the physical environment.    -   c) The system's video displays the virtual opponent's movement        along Path1(x,y,z,t) 278 to a virtual Position B 280.    -   d) In response, the Player moves along Path2(x,y,z,t) 282 to a        near equivalent physical Position C 284. The Player's objective        is to move efficiently along the same path in the physical        environment from start to finish as does the virtual opponent in        the virtual environment. However, since the virtual opponent        typically moves along random paths and the Player is generally        not as mobile as the virtual opponent, the player's movement        path usually has some position error measured at every sample        interval.    -   e) Once the virtual opponent reaches Position B 280, it        immediately changes direction and follows Path3(x,y,z,t) 286 to        a virtual Position D 288.    -   f) The Player perceives and responds to the virtual opponent's        new movement path by moving along Path4(x,y,z,t) 290 with        intentions to comply to virtual opponent's new movement path.    -   g) The system calculates at each sampling interval the Player's        new position, velocity, acceleration, and power. Within a volume        292 having radius R, either the measurement of peak acceleration        or the measurement of peak power, proportional to the product of        peak velocity and acceleration, characterizes First Step        Quickness.    -   h) The system provides real time numerical and graphical        feedback of the calculations of part g.

Dynamic Reactive Bounding is the player's ability to jump or bound inresponse to cuing that evokes a sport specific response in the player.In certain protocols of the present invention, measured constructsinclude the player's dynamic reaction time in response to the virtualopponent's jumps as well as the player's actual jump height and/or bounddistance and trajectory. Static measures of jumping (maximal verticaljump) have poor correlation to athletic performance. Dynamicmeasurements made within the present invention's simulation providesports relevant information by incorporating the variable of time withrespect to the jump or bound.

A jump is a vertical elevation of the body's center of gravity,specifically a displacement of the CM (Center of Mass) in the Y plane. Ajump involves little, if any, horizontal displacement. In contrast, abound is an elevation of the body's center of gravity having bothhorizontal and vertical components. The resulting vector will producehorizontal displacements in some vector direction.

Both the high jump and the long jump represent a bound in the sport oftrack and field. Satisfactory measures currently exist to accuratelycharacterize an athlete's performance in these track and field events.But in these individual field events, the athlete is not governed by theunpredictable nature of game play.

Many competitive team sports require that the athlete elevate his or hercenter of gravity (Y plane), whether playing defense or offense, duringactual game play. Examples include rebounding in basketball, a divingcatch in football, a volleyball spike, etc. Unlike field events, theathlete must time her or his response to external cues or stimuli, andmost frequently, during periods of pre-movement. In most game play, theathlete does not know exactly when or where he or she must jump or boundto successfully complete the task at hand.

It is universally recognized that jumping and bounding ability isessential to success in many sports, and that it is also a validindicator of overall body power. Most sports training programs attemptto quantify jumping skills to both appraise and enhance athletic skills.A number of commercially available devices are capable of measuring anathlete's peak jump height. The distance achieved by a bound can bedetermined if the start and end points are known. But no device purportsto measure or capture the peak height (amplitude) of a bounding exerciseperformed in sport relevant simulation. The peak amplitude can be asensitive and valuable measure of bounding performance. As is the casewith a football punt, where the height of the ball, i.e., the time inthe air, is at least as important as the distance, the height of thebound is often as important as the distance.

The timing of a jump or bound is as critical to a successful spike involleyball or rebound in basketball as its height. The jump or boundshould be made and measured in response to an unpredictable dynamic cueto accurately simulate competitive play. The required movement vectormay be known (volleyball spike) or unknown (soccer goalie, basketballrebound).

This novel measurement construct tracks in real time the actualtrajectory of a jump or bound performed during simulations of offensiveand defensive play. To measure the critical components of a jump orbound requires continuous sampling at high rates to track the athlete'smovement for the purpose of detecting the peak amplitude as well as thedistance achieved during a jumping or bounding event. Real timemeasurements of jumping skills include jump height, defined as theabsolute vertical displacement of CM during execution of a verticaljump, and for a bound, the peak amplitude, distance and direction.

Referring to FIG. 15, Dynamic Reactive Bounding may be determined asfollows.

-   -   a) A beacon, a component of the optical tracking system, is worn        at the Player's waist.    -   b) At Position A, software scaling parameters make the virtual        opponent 294, or virtual opponent's coordinates in the virtual        environment equivalent to the player's 296 coordinates in the        physical environment.    -   c) The system's video displays the virtual opponent's movement        along Path 1(x,y,z,t) 298 to a virtual Position B 300. The        virtual opponent's resultant vector path or bound is emphasized        to elicit a similar move from the Player 296.    -   d) In response, the Player 296 moves along Path2(x,y,z,t) 302 to        a near equivalent physical Position C 304. The Player's        objective is to move efficiently along the same path in the        physical environment from start to finish as does the virtual        opponent in the virtual environment. However, since the virtual        opponent typically moves along random paths and the Player is        generally not as mobile as the virtual opponent, the player's        movement path usually has some position error measured at every        sample interval.    -   e) The system calculates at each sampling interval the Player's        new position, velocity, acceleration, and power. In addition,        components of the Player's bounding trajectory, i.e., such as        air time, maximum y-displacement, are also calculated.    -   f) The system provides real time numerical and graphical        feedback of the calculations of part e. The Player's bounding        trajectory is highlighted and persists until the next bound is        initiated.

Dynamic Sports Posture is a measure of the player's sports postureduring performance of sport specific activities. Coaches, players, andtrainers universally acknowledge the criticality of a player's bodyposture during sports activities. Whether in a defensive or offensiverole, the player's body posture during sports specific movement directlyimpacts sport specific performance.

An effective body posture optimizes such performance capabilities asagility, stability and balance, as well as minimizes energy expenditure.An optimum posture during movement enhances control of the body centerof gravity during periods of maximal acceleration, deceleration anddirectional changes. For example, a body posture during movement inwhich the center of gravity is “too high” may reduce stability as wellas dampen explosive movements; conversely, a body posture duringmovement that is “too low” may reduce mobility. Without means ofquantifying the effectiveness of a body posture on performance relatedparameters, discovering the optimum stance or body posture is a “hit ormiss” process without objective, real time feedback.

Optimal posture during movement can be determined by continuous, highspeed tracking of the player's CM in relationship to the ground duringexecution of representative sport-specific activities. For each player,at some vertical (Y plane) CM position, functional performancecapabilities will be optimized. To determine that vertical CM positionthat generates the greatest sport-specific performance for each playerrequires means for continual tracking of small positional changes in theplayer's CM at high enough sampling rates to capture relevant CMdisplacements. It also requires a sports simulation that prompts theplayer to move as she or he would in actual competition, with abruptchanges of direction and maximal accelerations and decelerations overvarying distance and directions.

Training optimum posture during movement requires that the player striveto maintain their CM within a prescribed range during execution ofmovements identical to those experienced in actual game play. Duringsuch training, the player is provided with immediate, objective feedbackbased on compliance with the targeted vertical CM. Recommended rangesfor each player can be based either on previously established normativedata, or could be determined by actual testing to determine that CMposition producing the higher performance values.

Referring to FIG. 16, Dynamic Sports Posture during sport-specificactivities may be determined as follows:

-   -   a) A beacon, a component of the optical tracking system, is worn        at the Player's waist.    -   b) At Position A, software scaling parameters make the virtual        opponent 306, coordinates in the virtual environment equivalent        to the player's 308 coordinates in the physical environment.    -   c) The system's video displays the virtual opponent's movement        along Path1(x,y,z,t) 310 to a virtual Position B 312.    -   d) In response, the Player moves along Path2(x,y,z,t) 314 to a        near equivalent physical Position C 316. The Player's objective        is to move efficiently and in synchronicity city to the virtual        opponent's movement along the same path in the physical        environment from start to finish as does the virtual opponent in        the virtual environment. However, since the virtual opponent 306        typically moves along random paths and the Player 308 is        generally not as mobile as the virtual opponent, the player's        movement path usually has some position error measured at every        sample interval.    -   e) The system calculates at each sampling interval the Player's        most efficient dynamic posture defined as the CM elevation that        produces the optimal sport specific performance.    -   f) The system provides real time numerical and graphical        feedback of the calculations of part e.

Once the optimal Dynamic Posture is determined, training optimal DynamicPosture may be achieved by the following steps:

-   -   a) A beacon, a component of the optical tracking system, is worn        at the Player's waist.    -   b) The Player 308 assumes the dynamic posture that he/she wishes        to train.    -   c) The system provides varying interactive movement challenges        over sport specific distances and directions, including        unplanned movements.    -   d) lane positions, velocity, accelerations and power        measurements that are greater or less than or equal to the        pre-set threshold or window will generate real-time feedback of        such violations for the Player 308.    -   e) The system provides real-time feedback of compliance with the        desired dynamic posture during performance of the protocols.

Functional Cardio-respiratory Status (Fitness) is the player'scardio-respiratory status during the aforementioned sports specificactivities. In most sports competitions, there are cycles of highphysiologic demand, alternating with periods of lesser demand. Cardiacdemand is also impacted upon by situational performance stress andattention demands. Performance of the cardiorespiratory system undersports relevant conditions is important to efficient movement.

Currently, for the purpose of evaluating the athlete'scardio-respiratory fitness for sports competition, stationary exercisebikes, treadmills and climbers are employed for assessing cardiacresponse to increasing levels of physical stress. Though such exercisedevices can provide measures of physical work, they are incapable ofreplicating the actual stresses and conditions experienced by thecompetitive athlete in most sports. Accordingly, these tests areseverely limited if attempts are made to correlate the resultantmeasures to actual sport-specific activities. It is well known thatheart rate is influenced by variables such as emotional stress and thetype of muscular contractions, which can differ radically in varioussports activities. For example, heightened emotional stress, and acorresponding increase in cardiac output, is often associated withdefensive play as the defensive player is constantly in a “coiled”position anticipating the offensive player's next response.

For the cardiac rehab specialist, coach, or athlete interested inaccurate, objective physiological measures of sport-specificcardiovascular fitness, no valid tests have been identified. A validtest would deliver sport-specific exercise challenges to cycle theathlete's heart rate to replicate levels observed in actual competition.The athlete's movement decision-making and execution skills, reactiontime, acceleration-deceleration capabilities, agility and other keyfunctional performance variables would be challenged. Cardiac response,expressed as heart rate, would be continuously tracked as would keyperformance variables. Feedback of heart rate vs. sport-specificperformance at each moment in time will be computed and reported.

It will be appreciated that feedback regarding heart rate may beprovided independent of feedback regarding sports-specific performance.

Functional Cardio-respiratory Fitness is a novel measurement constructcapable of quantifying any net changes in sport-specific performancerelative to the function of the cardio-respiratory system. FunctionalCardio-respiratory Status may be determined as follows:

-   -   a) A beacon, a component of the optical tracking system, is worn        at the Player's waist.    -   b) A wireless heart rate monitor 36A (FIG. 2) is worn by the        Player. The monitor communicates in real-time with the system.    -   c) The system provides sport-specific exercise challenges to        cycle the Player's heart rate to replicate levels observed in        actual sport competition.    -   d) The system provides interactive, functional planned and        unplanned movement challenges over varying distances and        directions.    -   e) The system provides real-time feedback of compliance with a        selected heart-rate zone during performance of defined        protocols.    -   f) The system provides a real-time numerical and graphical        summary of the relationship or correlation between heart rate at        each sample of time and free-body physical activity.

Dynamic Reactive Cutting is a measure of the player's ability to executean abrupt change in position, i.e., a “cut” can be a directional changeof a few degrees to greater than 90 degrees. Vector changes can entailcomplete reversals of direction, similar to the abrupt forward andbackward movement transitions that may occur in soccer, hockey,basketball, and football. The athlete running at maximum velocity mustreduce her or his momentum before attempting an aggressive directionalchange, this preparatory deceleration often occurs over several gaitcycles. Once the directional change is accomplished, the athlete willmaximally accelerate along his or her new vector direction.

Accurate measurement of cutting requires continuous tracking of positionchanges in three planes of movement; ascertaining the angle scribed bythe cutting action; and measuring both the deceleration during brakingprior to direction change and the acceleration after completing thedirectional change.

For valid testing, the cues (stimuli) prompting the cutting action mustbe unpredictable and interactive so that the cut can not be pre-plannedby the athlete, except under specific training conditions, i.e.,practicing pass routes in football. It must be sport specific,replicating the types of stimuli the athlete will actually experience incompetition. The validity of agility tests employing ground positionedcones and a stopwatch, absent sport-relevant cuing, is suspect. Withknowledge of acceleration and the player's body weight, the powerproduced by the player during directional changes can also bequantified.

Referring to FIG. 17, Vector Changes and Dynamic Reactive Cutting may bedetermined as follows:

-   -   a) A beacon, a component of the optical tracking system, is worn        at the Player's waist.    -   b) At Position A, software scaling parameters make the virtual        opponent 318, or virtual opponent's coordinates in virtual        environment equivalent to the player's 320 coordinates in the        physical environment.    -   c) The system's video displays the virtual opponent's movement        along Path1(x,y,z,t) 322 to a virtual Position B 324.    -   d) In response, the Player 320 moves along Path2(x,y,z,t) 326 to        a near equivalent physical Position C 328. The Player's        objective is to move efficiently along the same path in the        physical environment from start to finish as does the virtual        opponent 318 in the virtual environment. However, since the        virtual opponent typically moves along random paths and the        Player is generally not as mobile as the virtual opponent, the        player's movement path usually has some position error measured        at every sample interval.    -   e) Once the virtual opponent 318 reaches Position B 324, it        immediately changes direction and follows Path3(x,y,z,t) 330 to        a virtual Position D 332.    -   f) The Player perceives and responds to the virtual opponent's        new movement path by moving along Path4(x,y,z,t) 334 to physical        Position E 336.    -   g) Once the virtual opponent 318 reaches virtual Position D 332,        it immediately changes direction and follows Path5(x,y,z,t) 338        to virtual Position F 340.    -   h) The Player perceives and responds to the virtual opponent's        new movement path by moving along Path6(x,y,z,t) 342 to physical        Position G 344.    -   i) Subsequent virtual opponent 318 movement segments are        generated until sufficient repetition equivalency is established        for all vector movement categories represented during the        performance of sport-specific protocols, including unplanned        movements over various distances and direction.    -   j) The system calculates at each sampling interval the Player's        new position and/or velocity and/or acceleration and/or power        and dynamic reactive cutting.    -   k) The system provides real time numerical and graphical        feedback of the calculations of part j.

It should be noted that these motor-related components of sportsperformance and fitness (which may be or may be derived from movementparameter(s)) are equally important to safety, success and/orproductivity in demanding work environments, leisure sports, and manyactivities of daily living.

The performance-related components are often characterized as either thesport-specific, functional, skill or motor-related components ofphysical fitness. These performance-related components are obviouslyimportant for safety and success in both competitive athletics andvigorous leisure sports activities. It should be equally obvious thatthey are also essential for safety and productive efficiency indemanding physical work activities and unavoidably hazardous workenvironments such as police, fire and military—as well as formaintaining independence for an aging population through enhancedmobility and movement skills.

First Person Perspective

Another embodiment of the invention involves a personal perspective,also known as a first person perspective. This perspective is a view onthe display of the virtual space from the perspective of the player. Itis in contrast to the type of information shown on the display 28 inFIGS. 2-4, which is generally termed a third person perspective. In athird person perspective the view of the virtual space is from someviewpoint outside of the playing field, akin to the view a spectatorwould have. The viewpoint is generally fixed, although the viewpoint maymove as action in the virtual space shifts to different parts of thevirtual space. For example, the third person perspective in a basketballsimulation may shift between two half-court views, depending on wherethe ball and the players are in virtual space.

In a third person perspective the movement of the icons in virtual spaceis represented by the movement of icons within the generally fixed view.Thus movement of a player icon to a different location in virtual spaceresults in movement of a corresponding player icon within the view fromthe generally fixed viewpoint.

However, a first person view is a view from a perspective within thesimulation. A system 360 including first person viewing is shown in FIG.18. Such a perspective is generally that of a participant in thesimulation, such as a player 362. The player 362 moves within a physicalspace 366, such movement being detected by a tracking system asdescribed above. As the player 362 moves to a new location 368, forexample, the view on a display 370 is altered to show virtual space fromthe viewpoint in virtual space corresponding to the new location 368.Thus the viewpoint will correspond to that of a virtual being(corresponding to the player) at a location in virtual spacecorresponding to the player's location in physical space.

A stationary object 372 in the virtual space will change its position onthe display to reflect its position relative to the new viewpoint. Amovable object in virtual space such as a protagonist 376 also changesits position on the display 370 in response to a shift in viewpointcaused by movement of the player 362. In addition, the protagonist 376also is able to change its position within the virtual space. A changein position by the protagonist will also result in a change of itsposition on the display 370.

The system 360 may also display a representation indicating part of thevirtual being corresponding to the player 362, for example the hands 378shown on the display 370 in FIG. 18. Such display elements may be used,for example, to indicate items held by the virtual being in the virtualspace, to indicate position of part of the player's body (e.g., whetherthe hands are raised), or to indicate orientation of the player. Therepresentation may resemble part of a human body, e.g., hands, feet,etc. Alternatively the representation may be of other objects, e.g.,wings, abstract shapes, etc. The representation may or may not be alwaysin the displayed view.

The display of a first person perspective increases the fidelity of thesimulation, by making the view on the display closer to that which wouldbe perceived by the player in a real life activity.

Multiple Player Encounters

It will be appreciated that it is possible to have simulations or gamesusing the above systems where multiple players participate at once. Suchmultiple players may merely be displayed together, not interacting, ormay alternatively interact by competing against one another or bycooperating in a task or tasks.

As shown in FIG. 19, a system 380 has multiple players 382 and 384 whichparticipate using the same physical space 386 and display 388. Displayedplayer icons 390 and 392 correspond to the positions of the players 382and 384. It will be appreciated that it is desirable for the trackingsystem associated with the system 380 to be able to differentiatebetween the players 382 and 384.

It will be appreciated that a system where the players share the samephysical space presents the potential of the players colliding, possiblyleading to injury. Accordingly, FIG. 20 shows an alternate embodiment, asystem 400 in which multiple players 402 and 404 participatesimultaneously in separate respective physical spaces 406 and 408.

The physical spaces 406 and 408 may be located in the same room, inwhich case it may be possible to have one tracking system track theposition of both of the players. However, it may be more effective tohave separate tracking systems for each of the physical spaces. This isshown in the illustrated embodiment, with tracking systems 410 and 412corresponding to respective physical spaces 406 and 408. It will beappreciated that separate tracking systems will generally be needed ifthe physical spaces 406 and 408 are in different locations, such as indifferent rooms or in different buildings.

The tracking systems 410 and 412 are operatively coupled to a computer416 (which consist of two separate computer units in communication withone another and/or with a central computer unit). The computer 416 inturn is operatively coupled to displays 418 and 420 which correspond tothe physical spaces 406 and 408, respectively. The operative couplingbetween the computer 416, and the tracking systems 410 and 412 and thedisplays 418 and 420 may be accomplished by means of hard-wired cablesbetween these components. Alternatively, it will be appreciated that theoperative coupling may employ other means such as modems and telephonelines, radio or infrared light signals, or connections to computernetworks such as the World Wide Web. Thus such connections may be madeover long distances, allowing players separated by a large physicaldistance to participate in a simulation in the same virtual space. Itwill be appreciated that more than one computer or processor may beused, especially with systems connected over large distances.

The displays 418 and 420 may show the same view of virtual space, suchas a the same third person perspective. Alternatively and preferably,the displays 418 and 420 may show different views of the virtual space.For example, for a simulated tennis match each of the displays may showa third person perspective view from the end of the court correspondingto the respective physical spaces. Alternatively, different first personperspective views of the physical space may be shown on each of thedisplays. Thus each display may have a viewpoint in virtual spacecorresponding to the location of the player viewing that display.

It will be appreciated that more than two players may be involved in thesame simulation, with additional physical spaces, displays, trackingsystems, and/or computers added as appropriate. For example, each playermay have an individual game unit (a display, tracking system, andphysical space), while all the players share a computer or computers. Itwill be appreciated that even when more than one physical space is used,more than one player may occupy each physical space. For example, asimulated tennis doubles match may involve two physical spaces, with twoplayers occupying each physical space.

It will be appreciated that the multiplayer simulation disclosed aboveallows the performance of more than one person to be evaluatedsimultaneously. In addition, the use of a live player as a virtualopponent results in a more realistic sports simulation. Despite advancesin technology and artificial intelligence, computers are unable tocapture the nuances of human thinking and behavior in general, andsports strategy in particular. Much of sports performance is governed bycompressed time frames—mere milliseconds—within which offensive anddefensive opponents are capable of a wide variety of movementsassociated with six degrees of freedom. Computers are as of yet unableto fully simulate this behavior.

Performance Scaling

FIG. 21 illustrates an alternate embodiment of the invention whichincludes performance scaling, also known as handicapping. There is shownin FIG. 21 a testing and training system 440 with performance scaling.One or more scaling factors define the relationship between movements ofa player 442 in a physical space 444 and changes in the virtual spaceposition corresponding to the player 442 (represented in FIG. 21 as theposition of player icon 446 in a representation of virtual space 450shown on a display 452).

If the player 442 makes a small jump, such as to position 442′, thiscould be represented in virtual space and displayed as a much largerjump to position 446′. A scale factor could be used to control therelationship between the actual jump height and the apparent jump heightin virtual space. Such scaling may be linear or nonlinear.

Similarly, movement by the player 442 along a path 456 may be displayedthrough use of a scale factor as movement of a greater or lesserdistance, such as movement along a virtual path 458.

The scale factors may be different for movement in different directions.In addition, the scale factors may be adjusted to take into accountdifferences in skill levels and training levels of different players anddifferent avatars or protagonists. Thus through use of scale factors achild may be enabled to compete evenly in a virtual basketball gameagainst a protagonist having the ability of Michael Jordan, for example.

Scaling may also be used to provide positive feedback which encouragesfurther efforts. For example, a person undergoing rehabilitation afteran injury is likely to react positively to a large apparent result invirtual space to a physical effort that produces only a small movement.Such a person may thereby be encouraged to continue exercising andimproving skills when he or she might otherwise become discouraged.

Scaling may be adjusted during an individual protocol, or during aseries of protocols making up a training session. Such adjustments maybe made in response to increased performance, for example due toacquisition of new skills, or decreased performance, for example due tofatigue or injury.

It will be appreciated that scaling may be integrated with themultiplayer systems described above so as to handicap one of theopponents relative to the other. This handicapping may be used to makecompetitive an encounter between two opponents of unequal skill, such asa parent and a child, or a fan and a trained athlete. Through scaling awily, though physically less adept, person, such as a coach, may moredirectly interact for teaching purposes with a more physically ablestudent.

It will be appreciated that there are many other permutations of theabove-described handicapping and scaling concepts. For example, amultiplayer tennis match may be handicapped by providing one of theplayers with a higher net (which would be perceived only in thatplayer's display). A scaled lag may be added to slow down the apparentquickness of one of the players. One player may have a maximum top speedfor changes of position in the virtual space.

Progression Algorithm

Using the above-described systems, protocols may be created that aredesigned to lead a player or subject through a series of motions. Forexample, a protocol may be used to drill a subject on a skill, such aslateral motion or timed leaping ability. Groups of protocols may becreated that involve skills specific to a certain sport, the groupsbeing selectable for playback as such by a user. For example, drillsinvolving basketball skills or drills involving baseball skills may begrouped, allowing an athlete with a particular interest or in trainingfor a specific sport to easily locate and playback drills for developingappropriate skills.

The invention allows modulation, over a continual range, of playback ofstored protocols. This modulation may be accomplished by the speed,amplitude, and/or direction of motion by an avatar or protagonist duringplayback of a protocol. Such modulation may be used to tailor anexercise program to the abilities of an individual user. For example, arehabilitating geriatric may be sufficiently challenged by playback of agiven protocol at 20% of the speed it was recorded at. However, an elitehealthy athlete may require playback of the same protocol at 140% of thespeed it was recorded at. User-specific modulation levels may berecorded for analysis of results and for recall for future trainingsessions of that user. As a user progresses the modulation of protocolsmay be changed to continue to provide the user with new challenges.

Playback of protocols may also be modulated during an individualprotocol or series of protocols in response to user performance. Forexample, comparison of current performance to past performance mayindicate that the user is ready to begin training at a new, higher levelof performance—modulation of playback of protocols may be revisedaccordingly to provide a new challenge within that training session.Alternatively, modulation may be revised in response to decreasedperformance, for example due to fatigue or injury.

Modulation of the playback of stored protocols allows a single protocolto be used by subjects having different skill levels. Thus results forvarious training sessions of one user, and the results of various usersof different skill levels, may readily be compared.

Recordation of Protocols

Further in accordance with the invention, a system 460 which is able torecord protocols for later playback, is shown in FIG. 22. In the system460 a trainer or protocol creator 462 wearing a beacon or reflector 463moves within a physical space 464, thereby creating a three dimensionalcontour pattern. The motion of the trainer 462 is tracked by a trackingsystem 466 as described above. The positional data output from thetacking system 466 is sent to a computer 470. The computer 470 includesa storage device such as a floppy disk drive, a hard disk drive, awriteable optical drive, a tape drive, or the like. Alternatively, thestorage device may be separate from the computer.

The storage device records the movement contours of the trainer 462 forlater playback. The position of the trainer 462 may also be representedon a display 472 by the location of an icon in a virtual space, thusproviding feedback to the trainer regarding his or her movements. Suchrecordation is preferably at a rate of at least 20 Hz, is morepreferably at a rate of at least 50 Hz, and is even more preferably at arate of 70 Hz.

The protocol so recorded by the system 460 may be played back, with themotion of an avatar following the recorded motion contour of the trainer462. The avatar following this recorded motion contour may be interactedwith by a player or subject. For example, the player may be trained toemulate the trainer's movements by attempting to maintain synchronicitywith the avatar's movements. A measure of compliance may be made betweenthe player's motions and the prerecorded motions of the trainer.

Thus the system 480 may be used as follows:

The protocol creator 462 dons the beacon 463 and “choreographs” adesired movement pattern while his or her positional changes over timeare recorded. This recording represents the creator's movement contourpattern.

A user attempts to follow (the synchronicity measurement construct), orsomehow interacts with, the pre-recorded movement contour pattern at aselected playback rate.

The user is provided with real time feedback as to his or hercompliance.

It will be appreciated that the recording feature of the system 480 maybe used to record motions of a subject for later playback, for reviewand/or evaluation by the subject or by others.

Measurement of Orientation

As indicated above, beacons may be used to measure orientation of bodyof the player or subject. Measurement of orientation is useful insituations where an appropriate response to a stimulus may simplyinvolve a twist or torque of the player's body. The ability to measureorientation is valuable in a number of respects.

Orientation may used to increase fidelity of simulation. Display of anicon representing the player or subject may be altered depending uponthe orientation of the player. In multiplayer simulations,representation of orientation imparts useful information to an opponent,since many maneuvers such as fakes and feints often mostly or totallyinvolve changes in orientation as opposed to changes in position.

For first person perspectives, taking orientation into account allowsthe view a player sees to be revised based on changes in orientation ofa player.

Since orientation is a part of posture, measurement and display oforientation is useful in training correct sports posture. Takingorientation into account in the display would provide better feedback tothe player regarding his or her orientation.

Measurement of player orientation may be used in determining certainmeasurement parameters, such as reaction time and first step quickness.

Measurement of orientation allows for calculation of rotationalaccelerations. Rapid, properly timed accelerations of the body center(the hips) are essential in many sports for speed and power development.As is known from the martial arts, rapid twisting of the hips isessential for both effective movement and power generation. First stepquickness may be redefined as an acceleration of the player's hips(translational or rotational) in the correct direction.

Measurement of Upper Extremity Movements

Referring to FIG. 23, a training system 480 is shown that tracksmovement of upper extremities (arms) of a player 482. The player 482wears a beacon or reflector 484 for tracking whole body motion, as isdescribed for many of the embodiments above. Additionally, the playerhas an upper beacon or reflector 488 on each of his or her upperextremities 490. The upper beacons 488 may be placed on the upper orlower arms, on the wrists, or on the hands, as desired. A tracking anddisplay system similar to those described above is used to track anddisplay motion of the upper extremities and of the whole body.

Tracking of movement of upper extremities provides enhanced simulationin activities where movement of the upper extremities is important, suchas boxing, tennis, handball, and activities that involve catching orusing the hands to move an object.

By use of the upper beacons 488 on one or both upper extremities,measurements may be extracted related to the player's ability to react,initiate and coordinate his or her upper extremities. The ability toquantify such performance is valuable for sports enhancement (footballlineman, boxers, handball players, etc.) and physical medicine(rehabilitation of shoulder and elbow injuries, etc.).

Specific parameters that may be measured or calculated taking intoaccount upper extremity movements include: Dynamic Reaction Time (howquickly the hands respond to cues); Vector Acceleration (magnitude ofthe acceleration of the hands/arms); Synchronicity (ability of hands tofollow interactive cues); and Cardio-Vectors (heart rate relationship towork performed by the hands).

The training system 480 may be modified to additionally or alternativelytrack the lower body extremities, as by use of lower beacons on thelegs, feet, hips, etc.

Movement Resistance

It is desirable to provide tactile and force feedback provide forenhancement of a virtual reality experience, allowing a subject orplayer to experience forces simulating those of the activities simulatedin virtual reality. For example, if a weight is lifted in the physicalworld, the subject feels a resistance to the movement (due to itsweight).

Referring to FIG. 24, a training system 500 is shown that includes meansto provide physical resistance to movements of a player or subject 502.The tracking and display components of the training system 500 aresimilar to those described further with respect other embodiments, andsuch description is not repeated for this embodiment.

The player 502 wears a belt 504 around his or her waist. One end of eachof one or more resistance devices 506 are attached to the belt. Theresistance devices 506 provide a force against which the player 502 mustpull in order to move. As shown the resistance devices 506 areelastomeric or elastic bands which provide an opposing force as they arestretched. The other end of the resistance devices 506 are attached toposts or stakes 510, which are preferably outside of the physical space512 on a floor (as shown), or on a wall or ceiling. As shown in FIG. 23,the posts or stakes 510 may slide freely in slots 516 outside of thephysical space 512.

The resistance devices 506 thus provide resistance to movement of theplayer 502. As the player moves within the physical space 512, one ormore of the resistance devices 506 is stretched. This stretchingproduces a force on the player 502 opposing his or her motion. Thisopposing resistance acts to progressively overload the subject or playerin each movement plane, thereby accelerating progress due to well-knownprinciples of athletic training.

Other suitable resistance devices include springs and gas-filledcylinders, as well as cords sold under the trademark SPORT CORDS.

Preferably, resistance devices would be provided for all three planes ofmovement (X, Y, Z). Resistance devices for providing resistance in theY-direction (resistance to jumping or leaping) may be anchored to thefloor in the vicinity of the player. Anchors for the resistance devicesmay be recessed in the floor.

It will be appreciated that resistance devices may be attached to theplayer at places other than the waist. For example, the resistancedevices may be attached to lower and/or upper extremities to provideresistance to movement of specific parts of the body.

Additionally or alternatively, resistance devices with both endsattached to different parts of the body may be used. Such a device maybe attached, for example, from arm to leg, from upper arm to lower arm,from upper leg to lower leg, from head to arm, from arm to waist, orfrom arm to other arm.

Use of resistance devices coupled with accurate measurement of locationof the player or subject allows enhanced accuracy of sports results inmore sports relevant movement patterns. The system 500 also allowsquantification of the effects of added resistance both in real time andprogressively over time.

The resistance devices may also be used to enhance the simulation bysimulating the apparent conditions encountered by the virtualcounterpart that the subject controls. For example, the resistanceprovided by the resistance devices may simulate the resistance thesubject's counterpart experiences while treading through mud, snow, orwaist deep water. With appropriate force feedback, the subject not onlysees the forces acting on his or her counterpart, but actually“experiences” these forces in the physical world. Such resistance may beprovided by one or more actuators such as piston-cylinder assemblies,motors, etc., connected to the player, the force exerted by theactuator(s) being controlled by the system to provide for a forcefeedback to the player or a force consistent with the virtual reality inwhich the player exists.

The resistance devices may also be used to provide handicapping inmultiplayer games, with levels of resistance chosen to compensate fordifferences in skill between the players.

Tracking Movement in Conjunction with Use of Exercise Apparatuses

The slide board is a widely used exercise apparatus which is used forconditioning and rehabilitation to help improve lateral movement, power,proprioception and endurance. As shown in FIG. 25, a typical slide board520 has a flat, slippery sliding surface 524 with stops boards 528 and530 on either end. A user uses a foot to push off the stop board 528,for example, glides or slides across the sliding surface 524, and thenchanges direction by pushing off the stop board 530 with the other foot.Slide boards are often used to simulate the physical demands of iceskating.

Another stationary exercise device involving back-and-forth movement isthe ski simulation device 540 shown in FIG. 26. The device 540 has atension-loaded skate 542 that glides laterally across an arc-shapedplatform 546. The skate 542 has foot pads 550 thereupon for a user standon. As the user moves back and forth, the skate 542 moves from side toside and the device 540 rocks back and forth on a curved or arcuatesurface 552 of the platform 546. Such devices are used for improvingbalance, motor skills, endurance, and muscle tone for the lower body. Anexample of such a device is one sold under the trademark PRO-FITTER.

The devices shown in FIGS. 25 and 26 may be used in conjunction with thetracking and display systems described earlier. Referring to FIG. 27, atraining and simulation system 560 is shown. The system 560 has trackingand display components similar to those described earlier with regard toother embodiments. A subject 562 interacts with an exercise device 564which is within in a physical space 568. The subject's movement istracked and displayed. The devices shown in FIGS. 25 and 26 anddescribed above are exemplary exercise devices. Such displaying mayinvolve either first person or third person perspectives, both describedabove.

Measurement constructs such as the Dynamic Sports Posture constructdescribed above may be used to analyze the movements of the subject 562.

A system such as the system 560 may be used to enhance the simulation ofa sports experience by displaying appropriate surroundings while usingthe exercise device 564. For example moguls, tree branches, otherskiers, etc. may be displayed during a skiing simulation. The speed ofapparent movement in the displayed virtual space may be tied to thespeed of movement of the subject.

Reactive Power Training

Typical exercise programs incorporate two primary components-isolatedlimb/joint resistive training (strength training) and aerobiccardiovascular (CV) training. Though generally popular, such programsare considered inferior for those seeking improved functional or sportspecific performance accompanied by substantial increases in lean bodymass (more muscle).

One reason that such programs are considered inferior is neither of thetraditional components meaningfully contributes to such core functionalcapabilities as balance, reaction time, agility and reactive power. Thetraditional strength training component of isolated joint/limb trainingcomponent is designed to increase the amount of load that can be lifted,not to appreciably enhance the individual's ability to efficiently and,where required, explosively negotiate his or her environment. Strengthtraining does not train the nervous system to efficiently work inconjunction with the muscle fibers to produce optimum functionalperformance.

Additionally, for those seeking the lean, muscular, powerful physiquesof the elite sprinter, gymnast or body builder, the traditional aerobicCV component may be counter-productive. In his book Explosive Power &Strength, Dr. Donald Chu noted that “aerobic training has become adominant component of most conditioning programs . . . . However, exceptin the early stages of their careers, aerobic training for strength andpower athletes is out of the question. Aerobic training may help anathlete recover from high-intensity exercise, but it does so at theexpense of speed and power and increases the risk of overuse injuriesand overtraining. Endurance training is important, but . . . be certainthat the type of endurance developed is specific to the sport.”

Consequently, the most efficient and effective meaning of developing thelean powerful, functional bodies that many fitness club members covet,and that many athletes and seniors require, involves training for power.Power training, simply stated, is comprised of multiple, relativelybrief bouts (periods) of high intensity exercise. For example, sprintersrun at the fastest possible pace for a brief period of time—the resultis significant muscle hypertrophy. By contrast, distance runners work ata sustainable pace, doing a nominal amount of work per unit of time. Itis this specificity of training that produces the contrasting long, thinthigh muscles of the marathon runner and the highly defined, largemuscles of the sprinter.

Referring to FIG. 28, a reactive power training system 600 is shown. Thetraining system 600 includes both reactive training devices 602 andstrength training devices 604.

The reactive training devices 602 provide cues to a subject (alsoreferred to as a user or player) to perform movements in response. Forexample, the reactive training devices may involve the subjectattempting to mimic the movements of an avatar on a display screen. Thecues are provided for numerous movements over a short period of time.

Preferably, the cues include prompts for numerous both planned andunplanned movement challenges. Preferably cues will be to elicitmovements that elevate the subject's heart rate to a desired targetzone. The cues may include auditory and/or visual cues.

The cues will preferably elicit movements in at least two dimensions.Examples of such two-dimensional movements include movement within arectangular floor area, movement along a line combined with jumping, andmovement along a line (such as by sliding) while maintaining a desiredposture. It will be appreciated that there are many such other movementsin at least two dimensions which may be cued by the reactive trainingdevice.

The reactive movements prompted by the reactive training devices mayinclude training scenarios designed to enhance sports specific skills.For example, soccer skills may be enhance by engaging the user in asimulated soccer game.

As shown in FIG. 28, the reactive training devices 602 each include aphysical space 610 and a tracking and display system 612. The trackingand display system 612 continually tracks the position of the subjectduring training. To facilitate tracking, the subject may wear a marker,such as a reflector, emitter, or beacon, the location of which istracked by the reactive power device.

The marker may emit or transmit a signal which enables the reactivetraining system to identify a particular subject. For example, themarker may emit sound waves (either sonic or ultrasonic) or light waves(either visible or non-visible) that the reactive training system isable to associate with the particular subject. Thus within a singletraining session a user may be able to interrupt a particular reactivetraining scenario after a bout of reactive training, with the reactivetraining device able to later “recognize” the user and continue thescenario from the point of interruption.

Alternatively or in addition, the recognition of a particular user maybe used to call forth a reactive training scenario or sequenceparticular to that user.

It will be appreciated that the marker may emit or transmit otherinformation, such as the heart rate of the wearer. However, a heartmonitor worn by the subject may have a separate telemetry system.

It will be appreciated that a user may be identified to a reactivetraining device by other means, such as by entry of identificationnumber on a keypad or touch screen, or by insertion into the device ofan object bearing indicia, such as a bar code or a magnetic medium,which identifies the user.

The numerous testing and training system embodiments described above aresuitable for use as reactive training devices. Many of the features ofthe testing and training systems, such as providing real-time feedbackto the subject or user, are desirable as well in the reactive trainingdevice.

It will appreciated that alternatively other devices that provide cuesthat elicit responsive movements from subjects are suitable for use asreactive training devices in the reactive power training system.

The reactive training devices may provide real-time feedback to thesubject during use of the reactive power training device. The feedbackmay related to one or more of the constructs described above. Forexample, the feedback may be indicative of the subject's reactive power,with the feedback possibly including an indication of the subject'sacceleration, velocity, or power.

Although as illustrated all of the reactive training devices are thesame, it will be appreciated that all of the reactive training devicesneed not be identical. In addition, a greater or lesser number ofreactive training devices may be employed.

Examples of suitable strength training devices include the Total Gym,Cybex or LifeFitness selectorized strength machines, BowFlex, freeweight bars and dumbbells, pulleys, elastomeric cables, chin bars andthe like. Preferably the strength training devices are capable oftraining various of the user's muscles. For example, some of thestrength training devices may be directed to working the upper bodymuscles, while others may be directed to working the lower body muscles.

Referring to FIG. 29, the reactive power training system 600 includes anetwork administration computer 620 which is coupled to the reactivetraining devices 602 to form a network 622. The network allowsinformation received at the reactive training devices (such asidentification information or performance information) to be stored in astorage device 624 that is part of the network administration computer620. This stored information may be accessed by any of the reactivetraining devices 602 in order to provide the user with cues appropriatefor the user's desired exercises. In addition, the stored informationmay be used to modulate the cues based on the user's progress within atraining session and between sessions.

The network administration computer 620 includes a data entry device 626for entering and/or updating information in the storage device 624.Suitable data entry devices include keyboards, mice, touch screens, diskdrives, and CD-ROM drives.

The strength training devices 604 may also be coupled to the network622. Information about the strength training exercises performed (suchas the number of repetitions, the weight, the distance traveled, and/orthe setting of the machine) may thereby be transmitted to the storagedevice 624.

Information may also be sent along the network 622 to a suitable displayincluded as part of each of the strength training devices 604. Such asuitable display may be integrally incorporated with the rest of thestrength training device. Alternatively the display may be in thevicinity of the strength training device, alongside the strengthtraining device, for example. The information sent may include theinformation regarding the exercises to be performed, and/or may includeother information.

While the reactive power training system is preferably networked asdescribed above, it will be appreciated that reactive power trainingsystem may in whole or in part non-networked. For example, informationregarding the exercises performed on the strength training devices maybe recorded manually, with the information later entered into thenetworked storage device.

During the recommended two to three reactive power training sessions perweek, a subject follows a training sequence which preferably alternatesbetween 30 to 120 second bouts (periods) of exercise on reactivetraining devices 602, and resistive strength enhancing activities on thestrength training devices 604. These highly stimulating, engagingtraining sessions can be completed in approximately 35 to 50 minutes. Itis believed that resistive strength training prepares (fires up) themuscle fibers prior to reactive training to create a state where theneuromuscular system is most receptive to growth.

Thus use of the training system 600 transforms the strength and powerdeveloped through isolated joint/limb training into truly functionalreactive power. It develops the type of CV fitness that leads toenhanced sports performance for sports demanding repetitive explosivemovement. Further, it provides a time efficient, entertaining means ofcreating a well-defined, powerful physique.

The reactive training devices 602 direct the flow of tasks over eachtraining session, and over a series of the user's training sessions. Forexample, after a suitably-timed bout of exercise on the reactivetraining device the user may be prompted to proceed to a specificstrength training device. Such a prompt may be coupled with otherinformation, for example information regarding the performance of thejust-completed bout of exercise.

The network administration computer 620 may be programmed to directusers so that the strength training devices 604 are used efficiently.For example, the network administration computer may be programmed tosend a user to a strength training machine which is currently unused, ifthe unused machine is part of that user's training sequence and has notyet been used by that user in the present training session.

There is a valuable synergistic effect derived from of power reactivetraining. It is widely known that significant benefits to thecardiovascular system are derived from exercise that elevates thesubject's heart rate to the targeted zone for a period of approximately20 to 40 minutes. Preferably the bouts of reactive training aresufficiently strenuous to maintain the user's heart rate in the targetzone during the resistive strength training that occurs between bouts ofreactive training. As one purpose of the present invention to developreactive power, it is desirable for the CV training component (here useof the reactive training devices) to contribute to the subject's abilityto function successfully during anaerobic power activities. Further, theCV component ideally create a training environment (situation) thatreplicates the type of muscular contractions and anxiety that thesubject will actually encounter in competition or demanding workenvironment.

Exercise scientists and coaches have searched for a single variable thatcould accurately characterize both performance and fitness.

Currently, a subject's overall performance fitness must be characterizedby a number of performance variables. These variables may includemeasures of lower and/or upper body strength, aerobic or anaerobicendurance, speed or the like. Few of these measures share a commondenominator that would allow comparison between all training components.

With Reactive Power Training, there is one variable that is descriptiveof the exercise components that comprise the program. This singlevariable, power, is the common denominator that enable accurateassessment of the benefits a subject derives from both isolated limbstrength training, as well as the benefits derived from sport specificmovement training.

Current measures of progress do not provide such a global measure.Measures of isolated joint strength, i.e., a bench press or squat forexample, are not reflective of functional movement capabilities. Currentcore tests for athletes measure the amount of load that can be lifted orhow fast they can run. As such, these tasks are specialized strength andspeed measures and are not reflective of the subject's ability to movewith power and skill amidst his or her environment. Most often, noindication of movement skills is provided—balance, speed, coordination,agility, perception, recognition, cognition, etc. are all leftunmeasured.

The present invention can quantify isolated limb power, whichcontributes to the ability to move with skill and power, as well asreactive power, which is the ability to actually move with skill andpower. The above-described reactive power training system is uniquelycapable of measuring reactive power.

By monitoring the activities of the subject while performing tasks thatare reflective of that individual's skill domain, dynamic (reactive)power can be quantified. For an athlete, this entails sport specifictasks, with the measurement location being the kinematic description ofmovements of the pelvis during execution within a computer simulation.Consequently, both isolated limb strength and power are quantified, aswell as dynamic power. For the reasons given above, it is preferablethat strength training and reactive training be co-mingled andalternated within the same training session. However, it will beappreciated that a serial approach to training may be used. In such anapproach most of all of the strength training is done either before orafter the reactive training.

Real Time Segmented Feedback

Movement challenges created for the player by movement of the virtual;opponent or avatar may include many relatively short, discrete movementsegments or legs. These segments may prompt movement amounting to only afew inches of movement of the player's center of mass. These segmentsmay be without fixed start or end positions. However, start or endpositions may be approximated, for example, by positions where theplayer changes direction, or by movement of the player a given distanceaway from a position where he or she was at rest.

In achieving maximal performance gains, it is beneficial for the playerto be given sensitive, real time, accurate feedback. It is preferablefor real time feedback to be provided to the player very soon after hisor her completion of each movement segment, regardless of the segmentdistance (generally detected as a core displacement of the player'scenter of mass).

The present invention includes calculation of performance values (basedfor example on the parameters described above) by continuously samplingpositional changes in at least two planes of movement, and preferably inthree planes of movement.

On Screen Display of Performance Parameters

FIG. 30 shows a monitor or display 660 which provides feedback to aplayer (or user or subject) using a testing and training system such asthose described above. The monitor 660 may be similar to the monitor 28described above.

In addition to a view 662 of virtual space, the monitor 660 alsodisplays parameter indications 664 of one or more parameters.

The parameter indications 664 display information related to performanceparameters such as those described above. For example, the parameterindications may be useful in providing the above-described real timesegmented feedback.

The relation to measured performance parameters may be direct, forexample displaying an indication of the player's elevation.Alternatively, the relationship between performance parameters and thedisplayed information may be more attenuated. The displayed informationmay be of a derived or calculated parameter such as power. It mayalternatively be of some “game score” which is an indication of one ormore aspects of the player's performance.

The display of information in the parameter indications 664 ispreferably graphical, although the information may additionally oralternatively be displayed in other ways, such as numerically. As shown,the information in each of the parameter indications 664 is representedgraphically by changing the color of part of a displayed invertedtriangle 670.

The scaling of the parameter indications 664 may be changeable,accommodating for example the differences expected in performance ofdifferent players, and the different movements expected in differenttypes of testing and training scenarios.

The parameter indications 664 each include a flag 672 which provides anindication of the maximum value of the displayed parameter. For example,the flag for an indication of player elevation may display the maximumelevation of the player thus far. This elevation information is animportant parameter for posture training, training a player tomaintained a crouched position, for example. The elevation informationis also useful, for example, for informing the player of his or herhighest jump.

It will be appreciated that the parameter indications need not includeflags, and may include additional flags. It will be further beappreciated that the flags may be used for a wide variety of otherpurposes, for example showing minimum parameter values.

The parameter indications 664 are preferably updated in real time, inorder to provide the player with timely feedback on performance.

The monitor 660 also displays a heart indication 678 which indicates theheart rate of the player. The heart indication may be graphical ornumerical, and may include an auditory signal, such as the simulatedsound of a beating heart. The heart rate of the player may be measuredand transmitted for display using a heart monitor such as that describedabove.

Although the invention has been shown and described with respect to acertain preferred embodiment or embodiments, it is obvious thatequivalent alterations and modifications will occur to others skilled inthe art upon the reading and understanding of this specification and theannexed drawings. In particular regard to the various functionsperformed by the above described elements (components, assemblies,devices, compositions, etc.), the terms (including a reference to a“means”) used to describe such elements are intended to correspond,unless otherwise indicated, to any element which performs the specifiedfunction of the described element (i.e., that is functionallyequivalent), even though not structurally equivalent to the disclosedstructure which performs the function in the herein illustratedexemplary embodiment or embodiments of the invention. In addition, whilea particular feature of the invention may have been described above withrespect to only one or more of several illustrated embodiments, suchfeature may be combined with one or more other features of the otherembodiments, as may be desired and advantageous for any given orparticular application.

1. A physical activity system comprising: a display; a tracking systemfor continuously tracking translation of a user relative to the display;and a computer operatively coupled to the tracking system and thedisplay, for updating in real time a view of a virtual space that isdisplayed on the display; wherein the computer shifts a viewpoint of theview based on the translation of the user.
 2. The physical activitysystem of claim 1, wherein the tracking system continuously tracks anoverall physical location of the user in a defined physical spacecorresponding to the virtual space; wherein the computer updates in realtime a user virtual location in the virtual space corresponding to thephysical location of the player in the physical space; and wherein theviewpoint of the view is from the user virtual location.
 3. The physicalactivity system of claim 1, wherein the view is a first person view. 4.The physical activity system of claim 3, wherein the first person viewis a first person perspective view.
 5. The physical activity system ofclaim 1, wherein the tracking system tracks the translations in threedimensions.
 6. The physical activity system of claim 1, wherein thetracking system includes a beacon worn by the user.
 7. The physicalactivity system of claim 1, wherein the tracking system includes acamera.
 8. The physical activity system of claim 1, wherein the viewincludes one or more stationary virtual objects that stay stationarywithin the virtual space.
 9. The physical activity system of claim 8,wherein the one or more stationary virtual objects change position onthe display in response to shifts in the viewpoint.
 10. The physicalactivity system of claim 1, wherein the view includes one or moremovable virtual objects that move within the virtual space.
 11. A methodof prompting physical activity, the method comprising: continuouslytracking translation of a user relative to a display, using a trackingsystem; and updating in real time a view of a virtual space using acomputer operatively coupled to the tracking system, wherein thecomputer shifts a viewpoint of the view based on the translation of theuser; and displaying the updated view of the virtual space on thedisplay.
 12. The method of claim 11, wherein the continuously trackingincludes continuously tracks an overall physical location of the user ina defined physical space corresponding to the virtual space; wherein theupdating includes updating in real time a user virtual location in thevirtual space corresponding to the physical location of the player inthe physical space; and wherein the viewpoint of the view is from theuser virtual location.
 13. The method of claim 11, wherein the view ofthe virtual space updated by the computer is a first person view. 14.The method of claim 13, wherein the first person view is a first personperspective view.
 15. The method of claim 11, wherein the continuouslytracking includes tracking the translations in three dimensions.
 16. Themethod of claim 11, wherein the tracking system includes a beacon wornby the user; and wherein the tracking includes tracking the beacon. 17.The method of claim 11, wherein the tracking system includes a camera;and wherein the tracking includes using image analysis to determine thetranslation of the user.
 18. The method of claim 11, wherein the viewincludes one or more stationary virtual objects that stay stationarywithin the virtual space.
 19. The method of claim 18, wherein the one ormore stationary virtual objects change position on the display inresponse to shifts in the viewpoint.
 20. The method of claim 11, whereinthe view includes one or more movable virtual objects that move withinthe virtual space.